Answer:
[tex]\boxed{V_{i} = 5\ m/s}[/tex]
Explanation:
Given:
Acceleration = a = 0.75 m/s²
Time = t = ?
Final Velocity = [tex]V_{f}[/tex] = 72 km/hr = 20 m/s
Required:
Initial Velocity = [tex]V_{i}[/tex] = ?
Formula:
a = [tex]\frac{V_{f}-V_{i}}{t}[/tex]
Solution:
For [tex]V_{i}[/tex] the formula becomes:
[tex]V_{i} = V_{f}-at[/tex]
[tex]V_{i}[/tex] = 20 - (0.75)(20)
[tex]V_{i}[/tex] = 20 - 15
[tex]V_{i}[/tex] = 5 m/s
In Case: If you want it in km/hr:
[tex]V_{i}[/tex] = 5 * 3.6
[tex]V_{i}[/tex] = 18 km/hr
Answer:
5 m/s
Explanation:
acceleration = 0.75 m/s²
time = 20 s
final velocity = 72 km/h = 20 m/s
initial velocity = ?
Apply formula for initial velocity.
[tex]u=-at+v[/tex]
[tex]\sf a=acceleration\\t=time\\v=final \: velocity\\u=initial \: velocity[/tex]
Solve for u.
[tex]u=-(0.75)(20)+ 20[/tex]
[tex]u=-15+20[/tex]
[tex]u= 5[/tex]
Find the net force of the box and the acceleration. 10 points. Will give brainliest.
Answer:
38.6 N
2.57 m/s²
Explanation:
Draw a free body diagram of the box. There are four forces:
Weight force mg pulling down,
Normal force N pushing up,
Friction force Nμ pushing left,
and applied force P pulling at an angle 40°.
Sum of forces in the y direction:
∑F = ma
N + P sin 40° − mg = 0
N = mg − P sin 40°
The net force in the x direction is:
∑F = P cos 40° − Nμ
∑F = P cos 40° − (mg − P sin 40°) μ
∑F = P cos 40° − mgμ + Pμ sin 40°
∑F = P (cos 40° + μ sin 40°) − mgμ
Plugging in values:
∑F = (80 N) (cos 40° + 0.23 sin 40°) − (15 kg) (10 m/s²) (0.23)
∑F = 38.6 N
Net force equals mass times acceleration:
∑F = ma
38.6 N = (15 kg) a
a = 2.57 m/s²
The north pole of a bar magnet is rapidly introduced into a solenoid at one end (say A). Which of the following statements correctly depicts the phenomenon taking place?
(a) No induced emf is developed.
(b) The end A of the solenoid behaves like a south pole.
(c) The end A of the solenoid behaves like north pole.
(d) The end A of the solenoid acquires positive potential.
Answer:
The correct option is;
(b) The end A of the solenoid behaves like a north pole
Explanation:
According to Lenz's law we have that the induced emf direction in the solenoid due to the rapid introduction of the bar magnet will be such that the electric current induced will have a resultant magnet field that will oppose to the movement of the north pole of the bar magnet that resulted in the magnetic field
Therefore, the opposing magnetic pole to the north pole of a magnet is a north pole and the solenoid end A will act like the north pole.
electronegativity increases when atoms ___
A.have a small atomic radius
B.are located in the right on the periodic table
C.are located on the left on the periodic table
D.have a large atomic radius
your answer is.....
D. have a large atomic radius
although they also increase going from left to right so if D is incorrect, B might be your answer. it depends on context of the lesson.
Proved that
V = u+at
Answer:
[tex]\sf Proof \ below[/tex]
Explanation:
We know that acceleration is change in velocity over time.
[tex]\sf a=\frac{\triangle v}{t}[/tex]
[tex]\sf a=\frac{v-u}{t}[/tex]
v is the final velocity and u is the initial velocity.
Solve for v.
Multiply both sides by t.
[tex]\sf at=v-u[/tex]
Add u to both sides.
[tex]\sf at + u=v[/tex]
Answer:
Acceleration = v-u/t when we flip -u and t to right hand side
then -u changes to plus and denominator t changes to numerator
then then this equations becomes v=u+at
Explanation:
This mathematical model describes the changes that occur in a sample of
water as its temperature increases. Use this model to predict what will
happen to the motion of the molecules in a sample of water that is being
heated from 50° to 100°C.
200°C
vaporization
150°C
melting
100°C
Temperature (°C)
water vapor
50°C
liquid water
0°C-
--50°C
10
20
ice
30
Time (min)
40
50
60
70
O A. The motion will change very little.
O B. The molecules will stop moving.
O C. The movement of the molecules will gradually decrease.
O D. The movement of the molecules will gradually increase.
The correct answer is D. The movement of the molecules will gradually increase.
Explanation:
At the beginning of the model the state of matter of the water is solid, in this, particles have a defined arrangement and are together, which stops particles from moving freely and only allows them to vibrate. However, as the substance is heated the thermal energy (heat) increases in the sample, this causes particles to move more and the arrangement of it changes. Due to this, when the ice melts and there is liquid water particles move more than in solid states, which makes ice lacks a defined shape. Moreover, as the heat continues to increase the thermal and kinetic energy (movement) increases, indeed in gas state (water vapor) particles will move freely. This means the movement or kinetic energy in particles gradually increases in the model.
Answer: D
Explanation:
A submarine emerges 1/9 of its volume when it partially floats on the sea surface. For make it completely submerge it is necessary to allow a volume of 50,000 [L] to enter of sea water whose density is 1,026 [g / cm3]. What is the weight of the submarine?
Answer:
4,524,660 N
Explanation:
Assuming the submarine's density is uniform, 1/9th of the submarine's mass is equal to the mass of the displaced water.
m/9 = (1026 kg/m³) (50 m³)
m = 461,700 kg
mg = 4,524,660 N
Which of the following statements are true? (mark all that apply)
A) Adaptive optics corrects for atmospheric distortion by following the distortion of a bright star, possibly an artificial star created by a laser, and rapidly changing the shape of a mirror using computer-controlled actuators to compensate for the distortion.
B) Improvements in technology will eventually allow the entire electromagnetic spectrum to be observed from high mountaintop observatories.
C) X rays from astronomical objects can only be detected from telescopes in space or in high altitude rockets.
D) The best observing sites for optical telescopes are atop remote mountains.
E) Radio telescopes must be carried to high altitudes by balloons in order to detect this type of radiation.
Answer:
The answer(s) for this question are as followed: A, C, & D
Explanation:
I hope this helped, let me know if i missed any.
hey help me plzzzzz i will mark brainliest
Answer:
The answer to your question is given below.
Explanation:
Mechanical advantage (MA) = Load (L)/Effort (E)
MA = L/E
Velocity ratio (VR) = Distance moved by load (l) / Distance moved by effort (e)
VR = l/e
Efficiency = work done by machine (Wd) /work put into the machine (Wp) x 100
Efficiency = Wd/Wp x100
Recall:
Work = Force x distance
Therefore,
Work done by machine (wd) = load (L) x distance (l)
Wd = L x l
Work put into the machine (Wp) = effort (E) x distance (e)
Wp = E x e
Note: the load and effort are measured in Newton (N), while the distance is measured in metre (m)
Efficiency = Wd/Wp x100
Efficiency = (L x l) / (E x e) x 100
Rearrange
Efficiency = L/E ÷ l/e x 100
But:
MA = L/E
VR = l/e
Therefore,
Efficiency = L/E ÷ l/e x 100
Efficiency = MA ÷ VR x 100
Efficiency = MA / VR x 100
why does a hot air balloon fall when the air inside is not heated
The robot HooRU is lost in space, floating around aimlessly, and radiates heat into the depths of the cosmos at the rate of 13.5 W. HooRU's surface area is 1.51 m^2 and the emissivity of its surface is 0.209. Ignore the radiation HooRU absorbs from the cold universe. What is HooRU's temperature?
Answer:
165.73 K
Explanation:
The computation of HooRU's temperature is shown below:-
As per the stefan's law, the power radiated by black body radiations which is
[tex]P = eA\sigma T^4[/tex]
where
A indicates surface area
e indicates emissitivity
T indicates temperature
now, we will put the values in the above equation
[tex]13.5 = 0.209 \times 1.51 \times \sigma \times T^4[/tex]
After solving the above equation we will get temperature which results
= 165.73 K
Therefore for computing the HooRU's temperature we simply applied the above formula.
A ball is dropped from a height of 20m. If its velocity increases uniformly at the rate 10m/s2 with what velocity and after what time will it strike the ground?
Answer: 2 seconds
Explanation:
Since I've only memorized a couple of formulas for these things, I need to do the time first:
I'll use the formula Distance = (1/2) (acceleration) (time)²
20 m = (1/2) (10 m/s²) (time)²
Time² = (20 m) / (5 m/s²)
Time² = 4 sec²
Time = 2 seconds
Now ...
-- When the ball hits the ground, it has been falling for 2 seconds.
-- Its acceleration has caused its speed to increase by 10 m/s every second.
-- So after 2 seconds, its speed has grown to (2 s) (10 m/s²) = 20 m/s .
analyze this physics mystery and be marked brainliest
Answer:
The two middle chains are for suspension of the glass surface, while the fours chains at all corners prevents tilting
Explanation:
From the picture, the the frame bearing the glass surface is suspended by the two metal chains at the middle,
While the balance to avoid tilting to either directions is maintained by the four chains at all corners.
Spring balance measures weight, not the mass of a body.
Answer:
That is true and is easily explained by the next equation:
W= m*g
where
W= Weight
m=mass
g= gravitational acceleration
so, if you use a spring balance in another planet with a different gravitational acceleration the measured weight will be different.
Suppose a current-carrying wire has a cross-sectional area that gradually becomes smaller along the wire, so that the wire has the shape of a very long,truncated cone. How does the drift speed vary along the wire?
Answer:
It slows down as the cross-section becomes smaller is the correct answer to this question.
Explanation:
That current is the same in all parts of the wire under steady-state conditions.Thus the velocity of drift is approximately equal to the cross‐sectional region.vd = I /nAq . As the cross-section gets smaller it accelerates.the velocity is always _____ to the line of a circle
Answer:
tangent
Explanation:
hope it helps
Answer:
the answer is tangent
Explanation:
tangent means a straight line or plane that touches a curve or curved surface at a point, but if extended does not cross it at that point.
hope this helps please like and heart this answer and give 5 stars and brainliest pls i beg u thx!!! : )
2.0 MW is to arrive at a large shopping mall over two 0.100Ω lines. Estimate how much power is saved if the voltage is stepped up from 120 V to 1200 V and then down again, rather than simply transmitting at 120 V. Assume the transformers are each 99% efficient.
Answer:
55 MW.
Explanation:
So, we are given the following data or parameters Below;
=> "2.0 MW is to arrive at a large shopping mall over two 0.100Ω line.
=> " the voltage is stepped up from 120 V to 1200 V and then down again, rather than simply transmitting at 120 V."
=> "Assume the transformers are each 99% efficient."
STEP ONE: determine the current in the transmission line.
Output Current, i = Power/ voltage.
Output Current,i = (2.0 MW × 10^6 W/ 1 MW)/120.
Output Current,i = 1.66 × 10^4 A.
Therefore, current in the transmission line = output voltage × output current/99% × line voltage.
= 120 × 1.66 × 10^4/ 99% × 1200 = 1.68 × 10^3 A.
STEP TWO: determine the power loss in the two lines.
Power loss = i^2 × Resistance
Power loss = (1.66 × 10^4 )^2 × 0.1 × 2 = 5.5 × 10^7 watt.
STEP THREE: determine the power generated.
Power generated = 2 × 10^6 +5.5 × 10^7.
Power generated = 5.57 × 10^7 watt.
STEP FOUR: determine the step down transformer power.
= 2 × 10^6/99% = 2.02 × 10^6.
Thus, 2.02 × 10^6 + 5.57 × 10^5 = 2.58 × 10^6 watt.
STEP FIVE: Determine the total power and the saved power.
Total power = 2.58 × 10^6/ 99%= 2.6 × 10^6.
Saved power = 5.7 × 10^7 - 2.6 × 10^6 .
Conversion to MW gives saved power = 55 MW.
=
Whenever the alternating current frequency in a series RLC circuit is halved,
a. the inductive reactance is doubled and the capacitive reactance is halved.
b. the inductive reactance is doubled and the capacitive reactance is doubled.
c. the inductive reactance is halved and the capacitive reactance is halved.
d. the inductive reactance is halved and the capacitive reactance is doubled.
e. the reactance of the circuit remains the same.
Answer:
The correct option is
a. The inductive reactance is doubled and the capacitive reactance is halved
Explanation:
For a series RLC circuit, is a resonant circuit such that the impedance, Z, is minimum at the resonance frequency
Also we have that the capacitive reactance [tex]X_C[/tex], is given as follows;
[tex]X_c = \dfrac{1}{\omega \cdot C}[/tex]
Where;
ω = Angular frequency = 2πf
Where;
f = The frequency in the circuit
[tex]\therefore X_c = \dfrac{1}{2 \cdot \pi \cdot f \cdot C}[/tex]
The inductive reactance is also given as follows;
[tex]X_L = \omega \cdot L = 2 \cdot \pi \cdot f \cdot L[/tex]
Therefore, when the circuit frequency doubles, the inductive reactance doubles and the capacitive reactance halves
When the alternating current frequency in a series RLC circuit is halved, the inductive reactance is doubled and the capacitive reactance is halved.
What is an alternating current frequency?An Alternating current (ac) frequency is known to be the amount of cycles per second that can be found in an ac sine wave.
The Frequency is known to be the rate through which the current changes direction in terms of per second. It is said to be often measured in hertz (Hz). Note that the alternating current frequency in a series RLC circuit is halved, the inductive reactance increases and the capacitive reactance is reduced.
Learn more about alternating current from
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what is a primary source?
Answer:
A primary source is an original document such as diaries, speeches, manuscripts, letters, interviews, records, eyewitness accounts, autobiographies. Empirical scholarly works such as research articles, clinical reports, case studies, dissertation
Explanation:
Answer:
Scientific paper
Explanation:
A p e x
Define centre of gravity and centre of Bouyancy
Answer:
Center of Gravity is the point in a body where the gravitational force may be taken to act. Center of Buoyancy is the center of gravity for the volume of water which a hull displaces.
Four identical point charges (+6.0 nC) are placed at the corners of a rectangle which measures 6.0 m×8.0 m. If the electric potential is taken to be zero at infinity, what is the potential at the geometric center of this rectangle
The electric potential at the geometric center of this rectangle is determined as 43.2 V.
Potential at the center of the rectanglePotential at the center of the rectangle is calculated as follows;
Let the distance from each corner to the center = xLet the length = aLet the breadth = bDistance from each corner to the center is calculated as follows;
[tex]x = \sqrt{(a/2)^2 + (b/2)^2}[/tex]
Potential due to four point charges is calculated
[tex]V = \frac{kq}{x} \\\\V =4 (\frac{kq}{x} )\\\\V = 4(\frac{kq}{\sqrt{(a/2)^2 + (b/2)^2} } )\\\\V = \frac{4 \times 9\times 10^{9}\times 6\times 10^{-9}}{\sqrt{(6/2)^2 + (8/2)^2} } \\\\V = \frac{4 \times 9\times 10^{9}\times 6\times 10^{-9}}{5} \\\\V = 43.2 \ Volts[/tex]
Learn more about electric potential here: https://brainly.com/question/14306881
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Give reasons.
a) Sunlight does not fall on the ground where cloud forms shadow.
Answer:
Sunlight passing through a cloud is scattered in various directions. Some photons eventually find their way out the bottom of the cloud, some are reflected upwards, and some are absorbed, serving to warm the cloud. Since only a fraction of the light makes it to ground level, you have a shadow.
Explanation:
Hope it helps you
Squids propel themselves by expelling water. They do this by keeping water in a cavity and then suddenly contracting the cavity to force out the water through an opening. A 9 kg squid (including the water in the cavity) at rest suddenly sees a dangerous predator. If the squid expels 2 kg of water out of its body with a speed of 8 m/s, what would be its own escape speed
Answer:
v_squid = - 2,286 m / s
Explanation:
This exercise can be solved using conservation of the moment, the system is made up of the squid plus the water inside, therefore the force to expel the water is an internal force and the moment is conserved.
Initial moment. Before expelling the water
p₀ = 0
the squid is at rest
Final moment. After expelling the water
[tex]p_{f}[/tex] = M V_squid + m v_water
p₀ = p_{f}
0 = M V_squid + m v_water
c_squid = -m v_water / M
The mass of the squid without water is
M = 9 -2 = 7 kg
let's calculate
v_squid = 2 8/7
v_squid = - 2,286 m / s
The negative sign indicates that the squid is moving in the opposite direction of the water
What is the magnetic force on a particle that has 0.000500 C of charge and is moving at
2.50 10m/s to the right through a magnetic field that is 4.20 T and pointing away from
you? Specify both magnitude and direction in your answer.
Answer:
1.) F = 5.3×10^-3 N
2.) Positive y - direction
Explanation:
The parameters given are:
Charge q = 0.0005C
Velocity V = 2.5010 m/s
Magnetic field B = 4.2 T
Magnetic force F = BVqsinØ
F = BVq
since Ø = 90 degree
Substitute all the parameters into the formula
F = 4.2 × 2.5010 × 0.0005
Therefore, the magnetic force on a particle is F = 5.3 × 10^-3 N
2.) According to Fleming's left hand rule, the direction of the magnetic force will be perpendicular to the magnetic field which moving upward of the screen.
Answer:
it’s f=0.0005 x 2.5 x 10^5 x 4.20
F= 525 N
+ y direction (up)
Explanation:
got it right
Calculate the acceleration of a mobile that at 4s is 32m from the origin, knowing that its initial speed is 10m / s.
Answer:
5.5 m/s^2
Explanation:
I believe this is the answer > using the formula a= v-v0/t
Hope this helps!
Answer:
-1 m/s²
Explanation:
Given:
Δx = 32 m
v₀ = 10 m/s
t = 4 s
Find: a
Δx = v₀ t + ½ at²
32 m = (10 m/s) (4 s) + ½ a (4 s)²
a = -1 m/s²
A wave travels at 295 m/s and has a wavelength of 2.50 m. What is the frequency of the wave?
O 118 Hz
O 292 Hz
O297 Hz
O 738 Hz
Answer:
[tex]118\; \rm Hz[/tex].
Explanation:
The frequency [tex]f[/tex] of a wave is equal to the number of wave cycles that go through a point on its path in unit time (where "unit time" is typically equal to one second.)
The wave in this question travels at a speed of [tex]v= 295\; \rm m\cdot s^{-1}[/tex]. In other words, the wave would have traveled [tex]295\; \rm m[/tex] in each second. Consider a point on the path of this wave. If a peak was initially at that point, in one second that peak would be
How many wave cycles can fit into that [tex]295\; \rm m[/tex]? The wavelength of this wave[tex]\lambda = 2.50\; \rm m[/tex] gives the length of one wave cycle. Therefore:
[tex]\displaystyle \frac{295\;\rm m}{2.50\; \rm m} = 118[/tex].
That is: there are [tex]118[/tex] wave cycles in [tex]295\; \rm m[/tex] of this wave.
On the other hand, Because that [tex]295\; \rm m[/tex] of this wave goes through that point in each second, that [tex]118[/tex] wave cycles will go through that point in the same amount of time. Hence, the frequency of this wave would be
Because one wave cycle per second is equivalent to one Hertz, the frequency of this wave can be written as:
[tex]f = 118\; \rm s^{-1} = 118\; \rm Hz[/tex].
The calculations above can be expressed with the formula:
[tex]\displaystyle f = \frac{v}{\lambda}[/tex],
where
[tex]v[/tex] represents the speed of this wave, and [tex]\lambda[/tex] represents the wavelength of this wave.Answer:
118
Explanation:
A 0.10 g honeybee acquires a charge of 23 pC while flying. The electric field near the surface of the earth is typically 100 N/C, directed downward. What is the ratio of the electric force on the bee to the bee's weight
Answer:
Explanation:
force on charge q in electric field E = q E
force on charge of bee in given electric field
= 23 x 10⁻¹² x 100
= 23 x 10⁻¹⁰ N
weight of honey bee = .10 x 10⁻³ x 9.8
= 9.8 x 10⁻⁴ N
Ratio of force / weight of bee
= 23 x 10⁻¹⁰ / 9.8 x 10⁻⁴
= 2.347 x 10⁻⁶ .
The three-dimensional arrangement of electron groups around the central atom is called ____.
A. Election-pair repulsion
B. Electronegativity
C. Geometric design
D. Electron-group geometry
Answer:
D. Electron - group geometry
Explanation:
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To pull a box up a rough slope,the force required will be least when it is applied :
a) horizontaly
b) vertically
c) perpendicular to the plane
d) parallel to the plane
Answer:
The correct option is;
d) Parallel to the plane
Explanation:
The forces acting on the box of mass, m are;
Weight of the box acting an angle, θ, equal to the inclination of the plane to the perpendicular of the plane
Weight of the box acting along the plane = m×g×sin(θ)
The force of friction along the plane = μ×m×g×cos(θ)
The total force acting downward along the plane [tex]F_{down}[/tex], = m×g×sin(θ) + μ×m×g×cos(θ)
The Force needed to pull the box up along the plane F = The total force acting downward along the plane
F = m×g×sin(θ) + μ×m×g×cos(θ) = m×g×(sin(θ) + μ×cos(θ))
When the force, Fₐ is applied vertically, the force acting along the plane = Fₐ×cos(θ)
When the force is applied perpendicular, the force acting along the plane = Fₐ×sin(θ)
When the force is applied horizontally, the force acting along the plane = Fₐ×cos(θ)
When the force is applied parallel to the plane, the force acting along the plane = Fₐ
Therefore, since Fₐ > Fₐ×cos(θ) and Fₐ > Fₐ×sin(θ), for acute angles, we have that the least force is required when the force is acting parallel to the plane.
# A cheetah can start from rest and attain the velocity 72km/h in 2 seconds. Calculate the acceleration of cheetah
Answer:
[tex]10 \: [/tex] m/s ^2Explanation:
Solution,
When a certain object comes in motion from rest, in the case, initial velocity = 0 m/s
Initial velocity ( u ) = 0 m/s
Final velocity ( v ) = 72 km/h ( Given)
We have to convert 72 km /h in m/s
[tex]72 \: km \: per \: hour[/tex]
[tex] = 72 \times \frac{1000}{60 \times 60} [/tex]
[tex] = 20 [/tex] m/s
Final velocity ( v ) = 20 m/s
Time taken ( t ) = 2 seconds
Acceleration (a) = ?
Now,
we have,
[tex]a = \frac{v - u}{t} [/tex]
[tex]a = \frac{20 - 0}{2} [/tex]
[tex]a = \frac{20}{2} [/tex]
[tex]a = 10 [/tex] m/s ^2
Hope this helps...
Good luck on your assignment..
The definition of parallel lines requires the terms line and plane while the definition of perpendicular lines requires the undefined terms of line and point.
Answer with explanation:
Complete question is provided in the attachment below.
There are 3 undefined term in geometry :1) A Point 2) A line 3) A Plane.
When two lines are parallel they never meet , so the requirement to define them is lines and a plane on which they lie.
While when two lines are perpendicular , they intersect each other at a point by making a right angle between them.
So it required lines and a point to define it.