Answer:
the y axis, the x axis and the title.
If each of the charges is increased by two times and the distance between them is also increased by two times, the electromagnetic force between them Group of answer choices
Answer: The force does not change.
Explanation:
The force between two charges q₁ and q₂ is:
F = k*(q₁*q₂)/r^2
where:
k is a constant.
r is the distance between the charges.
Now, if we increase the charge of each particle two times, then the new charges will be: 2*q₁ and 2*q₂.
If we also increase the distance between the charges two times, the new distance will be 2*r
Then the new force between them is:
F = k*(2*q₁*2*q₂)/(2*r)^2 = k*(4*q₁*q₂)/(4*r^2) = (4/4)*k*(q₁*q₂)/r^2 = k*(q₁*q₂)/r^2
This is exactly the same as we had at the beginning, then we can conclude that if we increase each of the charges two times and the distance between the charges two times, the force between the charges does not change.
A toy car, mass of 0.025 kg, is traveling on a horizontal track with a velocity of 5 m/s. If
the track then starts to climb upwards, how high up the track can the car reach?
Answer:
1.25 m
Explanation:
This is the vertical height not the distance along the slope.
[tex]K=U\\\frac{1}{2}mv^{2} = mgh\\h = \frac{v^{2}}{2g}=\frac{25}{20}=1.25 m[/tex]
The height the car can reach if the the track starts to climb upwards is 1.2742 meters up.
What is kinetic and potential energy?Kinetic energy is energy possessed by a body by virtue of its movement. Potential energy is the energy possessed by a body by virtue of its position or its relation with its surrounding systems.
P.E. = mass × g × height
K.E. = 0.5 × mass × (velocity)²
Given that the toy car has a mass of 0.025 kg and is traveling on a horizontal track with a velocity of 5 m/s. Now, the car starts to climb up vertically, therefore, the kinetic energy will be converted to potential energy.
Kinetic Energy = Potential Energy
0.5 × mass × (velocity)² = mass × g × height
Cancel mass from both the sides,
0.5 × (velocity)² = g × height
0.5 × (5 m/s)² = 9.81 m/sec² × height
height = 1.2742 meters
Hence, the car will travel 1.2742 meters up.
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3.
A person drives north 6 blocks, then drives west 6 blocks.
The displacement is a straight line from the starting point to the finish in a
direction
O A northwesterly
O B southwesterly
O c northeasterly
OD southeasterly
A Shaolin monk of mass 60 kg is able to do a ‘finger stand’: he supports his whole weight on his two index fingers, giving him a total contact area of 4 cm 2 with the ground. Calculate the pressure he exerts on the ground (include units), and write your answer to two significant figures.
Answer:
1500000 Pa
Explanation:
The formula for pressure is force per unit area.
P=F/A where F is force and A is area
Given that ;
F= mass * acceleration due to gravity
F= 60 * 9.81 = 588.6 = 589 N
A= area = 4cm² = 0.0004 m²
P= F/A = 589 / 0.0004
P= 1471500
P=1500000 Pa
A jumbo egg (80 grams) is dropped from a height of 15 meters onto a 1 inch of foam. Using kinematics, determine the velocity of the egg the instant before impact.
Answer:
the velocity of the egg the instant before impact is 17.15 m/s.
Explanation:
Given;
mass of the egg, m = 80 g = 0.08 kg
height through which the egg was dropped, h = 15 m
The velocity of the egg before impact will be maximum, and the final velocity is given by the following kinematic equation;
v² = u² + 2gh
where;
u is the initial velocity of the egg = 0
v is the final velocity of the egg before impact
v² = 0 + 2 x 9.8 x 15
v² = 294
v = √294
v = 17.15 m/s
Therefore, the velocity of the egg the instant before impact is 17.15 m/s.
For which medical procedure would Doppler ultrasound be most useful?
A.
Finding a lung tumor
B.
Fixing a pulled muscle
C.
Locating a broken bone in a finger
D.
Detecting a blockage in a heart artery
Doppler ultrasound would be most useful in detecting a blockage in a heart artery.
What are the clinical uses of Doppler ultrasound?By monitoring the rate of change in pitch, a Doppler ultrasound may calculate how quickly blood flows (frequency). A sonographer with training in ultrasound imaging applies pressure to your skin with a tiny, hand-held instrument (transducer) roughly the size of a bar of soap across the area of your body being scanned, moving from one place to another as required.
As an alternative to more invasive treatments like angiography, which involves injecting dye into the blood arteries to make them visible on X-ray images, this test may be performed.
Your doctor may use a Doppler ultrasound to assess for artery damage or to keep track of specific vein and artery therapies.
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A 10 kg box initially at rest moves along a frictionless horizontal surface. A horizontal force to the right is applied to the box.A student calculates the impulse applied by force during the 2 seconds is 4 N.s. and that the impulse applied during the following 3 seconds is 6 Nâs.
Required:
a. What, if anything, is wrong with these calculations? If something is wrong, identify it and explain how to correct it. If these calculations are correct, explain why?
b. What is the difference between a perfectly elastic and an inelastic collision?
Answer:
The answer is below
Explanation:
a) Impulse is the total effect of force which has been acting on a body over a period of time. Impulse is the product of the force and the period of time applied. It is given by:
Impulse = force × time
Given that during 2 seconds, the impulse is 4 Ns, we can calculate the force applied.
Impulse = force × change in time
4 = force * 2
force = 4 / 2 = 2 N.
Hence the impulse applied during the following 3 seconds is:
Impulse = force × change in time = 2 * (2 + 3) = 2 * 5 = 10 Ns
The impulse applied during the following 3 seconds is 10 Ns not 6 Ns
b) In perfectly elastic collision, there is no loss in kinetic energy while in an inelastic collision there is loss in kinetic energy due to energy conversion or transfer.
In perfectly elastic collision the object does not stick together while in an inelastic collision the object stick together.
A car was moving at 14 m/s After 30 s, its speed increased to 20 m/s. What was the acceleration during this time ( need help fast!!!)
Answer:let initial velocity u=14m/s
Final velocity v=20m/s
Time taken t=30
Acceleration =a
V=u +at
a= (20-14)/30
a=0.2m/s^2
Explanation:
Acceleration is the change in velocity with respect to time.
A person lying on an air mattress in the ocean rises and falls through one complete cycle every five seconds. The crests of the wave causing the motion are 20.0 mapart. Determine (a) the frequency and (b) the speed of the wave. (Cutnell 16.6)
Answer:
a) the frequency of the wave is 0.2 Hz
b) the speed of the wave 4 m/s
Explanation:
Given that;
time period = to complete one cycle t = 5 sec
frequency f = 1/t
frequency f = 1 / 5sec
f = 0.2 Hz
Therefore the frequency of the wave is 0.2 Hz
b)
speed of wave V = λf
given that our wavelength is 20.0 m
we substitute
speed of wave V = 20.0 × 0.2
speed of wave V = 4 m/s
Therefore, the speed of the wave 4 m/s
100 POINTS. PLEASE EXPLAIN
Answer:
Explanation:
Note the charge balls on the top and bottom row are identical. So those charges cancel each other out. The only charges in the net electric field are the two in the middle row.
Electric field strength = k*Q/r^2
= (8.99 *10^9) * (3-(-3)) * 5*10^(-6) / (2*0.5)^2
= 269700 N/C
Answer:
Explanation:
(b) cuz the 1st n 3nd row cancel out, net electric field will go from +3Q to -3Q. the direction is right.
An athlete runs on track at a constant speed of 75 meters/min for 15 s. What is the total distance he covered during that time?
Answer:
45
Explanation:
1. Amy uses 30N of force to push a lawn mower 10 meters. How much work does she do?
Two force vectors are oriented such that the angle between their directions is 46 degrees and they have the same magnitude. If their magnitudes are 2.81 newtons, then what is the magnitude of their sum
Answer:
F = 5.17 N
Explanation:
If we know the magnitudes of both vectors, and the angle between them, we can find the magnitude of their sum, applying the cosine theorem, as follows:[tex]F =\sqrt{F_{1} ^{2} +F_{2} ^{2} + 2*F_{1} * F_{2} * cos \theta} (1)[/tex]
Replacing by the givens, F₁ = F₂ = 2.81 N, θ = 46º, we get:[tex]F =\sqrt{2.81 N ^{2} +2.81 N ^{2} + 2*2.81N* 2.81N* cos 46} = 5.17 N (2)[/tex]
A toy cannon uses a spring to project a 5.26 g soft rubber ball. The spring is originally compressed by 4.93 cm and has a stiffness constant of 7.90 N/m. When it is fired, the ball moves 14.6 cm through the horizontal barrel of the cannon, and there is a constant frictional force of 0.0328 N between barrel and ball.
(a) With what speed does the projectile leave the barrel of the cannon?
m/s
(b) At what point does the ball have maximum speed?
cm (from its original position)
(c) What is this maximum speed?
m/s
answer and process please
Answer:
a) [tex]v=1.102122995 \approx 1.10m/s[/tex]
b) [tex]x=0.0451m[/tex]
c) [tex]v_m=1.75m/s[/tex]
Explanation:
From the question we are told that
Mass of soft rubber[tex]M_r= 5.26g=>0.00526kg[/tex]
Spring compression [tex]d_C= 4.93 cm=>0.0493m[/tex]
Stiffness constant [tex]k= 7.90 N/m[/tex]
Ball Distance [tex]d=14.6=>0.146[/tex]
Frictional force [tex]f=0.0328 N[/tex]
a)Generally the equation for motion of the second ball according to Newton's law is given by
[tex]\frac{1}{2}kc^2-f\triangle x=\frac{1}{2} mv^2[/tex]
[tex]v=\sqrt{\frac{k*d_c^2-2f\triangle x}{m}}[/tex]
[tex]v=\sqrt{\frac{(7.90 )(0.0493)^2-2*(0.0328)(0.0493+0.146)}{0.00526}}[/tex]
[tex]v=1.102122995 \approx 1.10m/s[/tex]
b)Generally for speed to be at maximum spring force must equal frictional force
At distance
[tex]f=kc'[/tex]
[tex]d_c'=f/k[/tex]
[tex]d_c'=0.0328 /7.90[/tex]
[tex]d_c'=0.004151898734=>0.0042m[/tex]
Therefore
Ball is at maximum speed at
[tex]x=d_c-d_c'[/tex]
[tex]x=0.0493-0.0042[/tex]
[tex]x=0.0451m[/tex]
c)Generally maximum velocity is represented mathematically as
[tex]\frac{1}{2}kc^2-f\triangle x'=\frac{1}{2} mv'^2+\frac{1}{2}kc'^2[/tex]
[tex]\frac{1}{2} mv'^2 = \frac{1}{2}kc^2-f\triangle x'-\frac{1}{2}kc'^2\\[/tex]
[tex]v=\sqrt{\frac{k*d_c^2-2*f*x-kd_c'^2}{m}}[/tex]
[tex]v=\sqrt{\frac{7.90 *0.0493^2-2*(0.0328)*(0.0451)-7.90(0.0042)^2}{0.00526}}[/tex]
[tex]v=1.749685197m/s[/tex]
[tex]v_m=1.75m/s[/tex]
Which statements correctly describe the formula or name of a compound? Select all that apply.
OA. The formula of nitrogen trifluoride is NF 3
B. The formula of ammonia is NH3.
C. The name of AlF, is trialuminum fluoride.
D. The formula of calcium chloride is CaCl2
E. The name of Li, Se is lithium selenate.
OF. The formula of dinitrogen monoxide is NO
2
Results
G. The formula of sulfur trioxide is 30.
Cho
Аа
H. The formula of magnesium hydroxide is Mg(OH)2
G.
Answer:
A, B, D, and H
Explanation:
Statements A, B, D and H are all correct except the following:
Statement C is incorrect. The name of [tex] AlF_3 [/tex] is aluminium fluoride NOT "trialuminium fluoride".
Statement E is incorrect. The name of [tex] Li_2Se [/tex] is lithium selenide NOT "lithium selenate".
Statement F is incorrect. Dinitrigen monoxide, also known as nitrous oxide has a formula of [tex] N_2O [/tex] NOT [tex] NO_2 [/tex].
Statement G is incorrect. Sulfur trioxide formula is [tex] SO_3 [/tex].
A car accelerates uniformly from rest and reaches a speed of 9.9 m/s in 11.4 s. The diameter of a tire is 86.9 cm. Find the number of revolutions the tire makes during this motion, assuming no slipping. Answer in units of rev.
Answer:
Number of revolutions = 20.71 rev.
Explanation:
Given the following data;
Initial speed, u = 0m/s
Final speed, v = 9.9m/s
Time, t = 11.4secs
Diameter = 86.9cm to meters = 86.9/100 = 0.869m
To find the acceleration;
Acceleration, a = (v - u)/t
Acceleration, a = (9.9 - 0)/11.4
Acceleration, a = 9.9/11.4
Acceleration, a = 0.87m/s²
Now we would find the distance covered by the tire using the second equation of motion.
S = ut + ½at²
S = 0(11.4) + ½*0.87*11.4²
S = 0 + 0.435*129.96
S = 56.53m
The circumference of the tire is calculated using the formula;
Circumference = 3.142 * diameter
Circumference = 3.142 * 0.869
Circumference = 2.73m
Number of revolutions = distance/circumference
Number of revolutions = 56.53/2.73
Number of revolutions = 20.71 rev.
Therefore, the number of revolutions the tire makes during this motion is 20.71 revolutions.
The momentum of a car traveling at 20m/s is 24,500 kgm/s. What is the car's mass?
Answer:
1225kg
Explanation:
Given parameters:
Velocity of the car = 20m/s
Momentum = 24500kgm/s
Unknown:
Mass of the car = ?
Solution:
To solve this problem, we must understand that the momentum of a body is the quantity of motion that it possess.
So;
Momentum = mass x velocity
Mass of the car = [tex]\frac{Momentum }{velocity}[/tex] = [tex]\frac{24500}{20}[/tex] = 1225kg
fired, the ball moves 15.9 cm through the horizontal barrel of the cannon, and the barrel exerts a constant friction force of 0.032 8 N on the ball. (a) With what speed does the projectile leave the barrel of the cannon
Answer:
Explanation:
Where is the remaining part of the question? This is a very easy one
What is the wavelength of a wave that has a speed of 350 meters second and a frequency of 140 hert??
Wavelength is the distance between identical points (adjacent crests) in the adjacent cycles of a waveform signal propagated in space or along a wire. In wireless systems, this length is usually specified in meters (m), centimeters (cm) or millimeters (mm).
Hope this helped
If a car takes a banked curve at less than the ideal speed, friction is needed to keep it from sliding toward the inside of the curve (a real problem on icy mountain roads). (a) Calculate the ideal speed to take a 100 m radius curve banked at 15.0o. (b) What is the minimum coefficient of friction needed for a frightened dri
Answer:
a) The ideal speed = 16.21 m/s
b) Minimum co-efficient of friction = 0.216
Explanation:
From the given information:
The ideal speed can be determined by considering the centrifugal force component and the gravity component.
[tex]\dfrac{mv^2}{r}cos \theta = mg sin \theta[/tex]
[tex]v = \sqrt {gr \ tan \theta}[/tex]
[tex]= \sqrt{(9.8 \ m/s^2) (100) \ tan 15^0}[/tex]
= 16.21 m/s
(b)
Let assume that it requires 25 km/h to take the same curve.
Then, using the equilibrium conditions;
[tex]mg \ sin \theta = \dfrac{mv^2}{r} cos \theta + \mu ((\dfrac{mv^2}{r}) sin \theta + mg cos \theta)[/tex]
[tex]\mu = \dfrac{mg sin \theta - \dfrac{mv^2}{r} cos \theta }{((\dfrac{mv^2}{r}) sin \theta + mg cos \theta) }[/tex]
[tex]\mu = \dfrac{g sin \theta - \dfrac{ v^2}{r} cos \theta }{((\dfrac{v^2}{r}) sin \theta + g cos \theta) }[/tex]
[tex]\mu = \dfrac{(9.8 \ m/s^2 ) sin (15^0) - \dfrac{ \dfrac{(25 \times 10^3}{3600} \ m/s)^2 }{100 \ m } cos (15^0) }{((\dfrac{(\dfrac{25 \times 10^3}{3600} )^2}{100}) sin 15^0 + (9.8 \ m/s^2) cos 15^0 ) }[/tex]
[tex]\mathbf{\mu = 0.216}[/tex]
Suppose you wanted to increase the force between two point charges by a factor of 5. By what factor must you change the distance between them
Answer:
the distance between the two point charges will be reduced by a factor of [tex]\frac{1}{\sqrt{5} } = 0.447[/tex]
Explanation:
The force between two point charges is given by Coulomb's law;
[tex]F = \frac{kQ_1Q_2}{r^2}[/tex]
where;
k is Coulomb's constant
Q₁ and Q₂ are two point charges
r is the distance between the two charges
From the equation above, the following relationship between force and distance can be deduced;
F₁r₁² = F₂r₂²
F₁r₁² = (5F₁)r₂²
r₁² = 5r₂²
[tex]r_2^2 = \frac{r_1^2}{5} \\\\r_2 = \sqrt{\frac{r_1^2}{5}} \\\\r_2 = \frac{r_1}{\sqrt{5} } \\\\r_2 = \frac{1}{\sqrt{5} } \ r_1\\\\r_2 = 0.447( r_1)[/tex]
Thus, the distance between the two point charges will be reduced by a factor of [tex]\frac{1}{\sqrt{5} } = 0.447[/tex]
To increase the force between two point charges by a factor of 5, you have to change the distance between them by a factor of 0.447.
Coulomb law states that the force of attraction between two charges is directly proportional to the product of the charges and inversely proportional to the distance between them. It is given by:
F = kq₁q₂/r²
q₁, q₂ are charges, k is a constant and r is the distance between them.
Let us assume that:
F = kq₁q₂/r²
[tex]r=\sqrt{\frac{kq_1q_2}{F} }[/tex]
To increase the force by a factor of 5:
[tex]r=\sqrt{\frac{kq_1q_2}{5F} }\\\\r=0.447 \sqrt{\frac{kq_1q_2}{F} }[/tex]
Hence to increase the force between two point charges by a factor of 5, you have to change the distance between them by a factor of 0.447.
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You carry a 50 N backpack for 10000 meters in 500 secs. How much power did
you use?
The work done by the force of 50 N for a displacement of 10000 m is 500000 J. Then the power is 250 × 10⁷ W.
What is work done?Work done in physics is the product of force and displacement of an object. If a force applied on an object results in a displacement the force is said to be done some work on the object.
Work done W = F.ds
Given F = 50 N
displacement = 10000 m
Then w = 50 N × 10000 m = 500000 J
Power is the rate of energy or work needed to bring a displacement in an object. It is the product of work done and time.
w = 500000 J
time = 500 s
then power = w. t
p = 500000 J × 500 s = 250 × 10⁷ W
Therefore, the power of the action is 250 × 10⁷ W.
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Old-fashioned heating systems sent steam into radiators in each room of a house. In the radiators, the steam condense
back to water. Analyze this process and explain how it heated a room.
Need help
Answer:
The steam gives what is known as the LATENT HEAT OF VAPORIZATION TO THE ROOM
Explanation:
The term known as " latent heat if vaporization" deals with changes in a specific phase of matter to another one, that is from liquid to vapor. It can be defined as the quantity or the amount of heat required to change the liquid into vapor.
Therefore, when the system send the steam into radiators in each room of the house the steam gives what is known as the LATENT HEAT OF VAPORIZATION TO THE ROOM.
The steam which Is first of all condensed In order to produce the latent heat of vaporization is then sent back into the system and then comes out again to repeat the process in the paragraph above.
Which gas in Earth's atmosphere has increased over time due to burning fossil fuels?
BER
oxygen
O nitrogen
water vapor
O carbon dioxide
Answer:
The carbon dioxide levels have increased due to burning fossil fuels
Explanation:
Correct on edge 2021 hope this helps!✌️
The gas in Earth's atmosphere that has increased over time due to burning fossil fuels is carbon dioxide.
What is meant by global warming ?Global warming is defined as the phenomenon of heating up of the earth's surface in a long term due to the increased amount of emission of green house gases in the earth's atmosphere.
Here,
When more fossil fuels and the materials like coal are burned for the purpose of energy production, it will result to the production of an increased amount of carbon dioxide. This leads to the emission of huge amount of carbon dioxide in the earth's atmosphere. Since, carbon dioxide is a green house gas, the release of higher amount of carbon dioxide will lead to an increased concentration of green house gases. This causes an increase in the temperature of the atmosphere, resulting in the increased heating of the surface of earth. This uneven heating up of earth's surface is called global warming. This is the result of higher release of carbon dioxide in the earth's atmosphere.
Hence,
The gas in Earth's atmosphere that has increased over time due to burning fossil fuels is carbon dioxide.
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A 9.0-kg box of oranges slides from rest down a frictionless incline from a height of 5.0 m. A constant frictional force, introduced at point A, brings the block to rest at point B, 19 m to the right of point A. What is the speed of the box just before it reaches point A
I'm going to assume that, judging by the fact that the coefficient of friction and angle of the incline seem to be intentionally left out, the point A refers to a point at the bottom of the incline, and the point B is located 19 m away from A on a horizontal surface. If this is not the case, please be sure to correct me!
Let v denote the speed of the box at point A, x the distance the box slides (without friction) down the incline, and θ the angle of the incline.
Recall that
v ² - v₀² = 2 a ∆x
where
v = final speed
v₀ = initial speed
a = acceleration
∆x = displacement
While on the incline, the box starts at rest (v₀ = 0) and slides a distance x from the starting point to point A with acceleration a to attain some speed v.
Use the free body diagram to determine the acceleration. By Newton's second law, the net force on the object acting parallel to the incline
∑ F = m g sin(θ) = m a → a = g sin(θ)
where m = 9.0 kg and g = 9.8 m/s².
Write the distance x in terms of θ with some trigonometry:
sin(θ) = (5.0 m) / x → x = (5.0 m) / sin(θ)
Now plug a and x into the formula above to solve for v :
v ² = 2 g sin(θ) ((5.0 m) / sin(θ))
v ² = (10.0 m) g
v ≈ 9.9 m/s
An airplane maintains a speed of 669 km/h relative to the air it is flying through as it makes a trip to a city 675 km away to the north. (a) What time interval is required for the trip if the plane flies through a headwind blowing at 33.0 km/h toward the south
Answer:
1.06 h
Explanation:
Assuming that the airplane is traveling through the air, moving at a sites relative to the ground. The airplane is expected to make a displacement of 675 km due North.
Let north y be positive, and west x also be positive, then
With the wind blowing at 33 km/h due South. We then say,
The northern component of the velocity of the airplane you the ground is
669 km/h - 33 km/h = 636 km/h
Then, the time interval taken by the airplane to travel 675 km is
675 / 636 = 1.06 h
Therefore, we can conclude that the answer is 1.06 h
A space expedition discovers a planetary system consisting of a massive star and several spherical planets. The planets all have the same uniform mass density. The orbit of each planet is circular.
In the observed planetary system, Planet A orbits the central star at the distance of 2R and takes T hours to complete one revolution around the star. Planet B orbits the central star at the distance of R. Which of the following expressions is correct for the number of hours it takes Planet B to complete one revolution around the star?
a. 1/â8T
b. 1/2T
c. 1/3â4T
d. 2T
e. â8T
Answer:
T/√8
Explanation:
From Kepler's law, T² ∝ R³ where T = period of planet and R = radius of planet.
For planet A, period = T and radius = 2R.
For planet B, period = T' and radius = R.
So, T²/R³ = k
So, T²/(2R)³ = T'²/R³
T'² = T²R³/(2R)³
T'² = T²/8
T' = T/√8
So, the number of hours it takes Planet B to complete one revolution around the star is T/√8
The correct expression for the number of hours it takes Planet B to complete one revolution around the star is [tex]\frac{T}{\sqrt{8} }[/tex].
The given parameters;
position of planet A from central star, = 2Rtime taken for Planet A = Tnumber of revolutions at the given time = 1 revposition of planet B from central star, = RFrom Kepler's law, the period of planet is related to radius as follows;
[tex]\frac{T_1^2}{R_1^3} = \frac{T_2^2}{R_2^3} \\\\T_2 ^2 = \frac{T_1^2 \times R_2^3}{R_1^3} \\\\T_2 = \sqrt{\frac{T_1^2 \times R_2^3}{R_1^3} } \\\\T_2 = \sqrt{\frac{T_1^2 \times R_2^3}{R_1^3} }\\\\T_2 = T_1 \sqrt{\frac{ R_2^3}{(2R_2)^3} }\\\\T_2 = T_1 \sqrt{\frac{R_2^3}{8R_2^3} } \\\\T_2 = T_1 \sqrt{\frac{1}{8} } \\\\T_2 = \frac{T_1}{\sqrt{8} }\\\\T_B = \frac{T_A}{\sqrt{8} } = \frac{T}{\sqrt{8} }[/tex]
Thus, the correct expression for the number of hours it takes Planet B to complete one revolution around the star is [tex]\frac{T}{\sqrt{8} }[/tex].
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A Shaolin monk of mass 60 kg is able to do a ‘finger stand’: he supports his whole weight on his two index fingers, giving him a total contact area of 4 cm 2 with the ground. Calculate the pressure he exerts on the ground (include units), and write your answer to two significant figures.
Answer:
P = 1471500 [Pa]
Explanation:
We must remember that pressure is defined as the relationship between Force over the area.
[tex]P=F/A[/tex]
where:
P = pressure [Pa] (units of pascals)
F = force [N] (units of Newtons)
A = area of contact = 4 [cm²]
But first we must convert from cm² to m²
[tex]A = 4[cm^{2}]*\frac{1^{2} m^{2} }{100^{2} cm^{2} }[/tex]
A = 0.0004 [m²]
Also, the weight should be calculated as follows:
[tex]w = m*g[/tex]
where:
m = mass = 60 [kg]
g = gravity acceleration = 9.81 [m/s²]
Now replacing:
[tex]w = 60*9.81\\w = 588.6[N][/tex]
And the pressure:
[tex]P=588.6/0.0004\\P=1471500 [Pa][/tex]
Because 1 [Pa] = 1 [N/m²]
A 30 kg girl and a 40 kg boy stand on rollerskates, face one another, and push off each other. If the boy accelerates backward with an acceleration of 6 m/s 2 , what will be the acceleration of the girl?
Answer:
the acceleration of the girl is 8 m/s² in opposite direction.
Explanation:
Given;
mass of the girl, m₁ = 30kg
mass of the boy, m₂ = 40 kg
acceleration of the boy, a₂ = 6 m/s²
let acceleration of the girl = a₁
Apply Newton's third law of motion;
the force exerted by the girl is equal in magnitude to the force exerted by the boy but in opposite direction.
F₁ = -F₂
m₁a₁ = -m₂a₂
30a₁ = -(40 x 6)
30a₁ = -240
a₁ = -240 / 30
a₁ = -8 m/s² (the negative sign shows that the acceleration is in opposite direction)
Thus, the acceleration of the girl is 8 m/s² in opposite direction.
Paul and Ivan are riding a tandem bike together they're moving at a speed of 5 meters per second Paul and Ivan each have a mass of 50 kg what can I do to increase the bikes kinetic energy.
a: he can let Ivan off at the next stop
b: he can pedal harder to increase the speed to 10 meters per second
c: he could reduce the speed to 3 meters per second
d: he can pick up a third Rider
Recall the equation for Kinetic Energy: = m
Knowing this, we know that there are only two factors that can alter Kinetic Energy: mass and velocity. Looking at the equation, we can deduce that an increase in either mass or velocity would increase the overall Kinetic Energy as long as everything else stays constant.
a) He can let Ivan off at the next stop - Wrong. By letting Ivan off, mass decreases. Assuming Paul maintains the same speed as before, Kinetic Energy decreases.
b) He can pedal harder to increase the speed to 10 meters per second - Correct. By speeding up, "v" increases and the overall Kinetic Energy increases.
c) He could reduce the speed to 3 meters per second - Wrong. Looking at the equation, we know reducing speed would reduce Kinetic Energy
d) He can pick up a third rider - Correct, assuming they keep the same speed after picking up the third rider: if mass increases and velocity stays the same, then Kinetic Energy will increase.
Answers - B, D
If there's anything you don't understand here, just let me know :)