Answer:
(a) 441 W (b) 0.59 hP
Explanation:
Given that,
Mass of a woman, m = 60 kg
Height of a staircase, h = 15 m
Time, t = 20 s
(a) We need to find the power she expend. Work done per unit time is called power. It is given by :
[tex]P=\dfrac{W}{t}\\\\P=\dfrac{mgh}{t}\\\\P=\dfrac{60\times 9.8\times 15}{20}\\\\P=441\ W[/tex]
( b) Since, 1 hP = 745.7 W
P = 0.59 hP
A pendulum is transported from sea-level, where the acceleration due to gravity g is 9.80 m/s2, to the bottom of Death Valley. At this location, the period of the pendulum is decreased by 3.00%. What is the value of g in Death Valley
Answer: the value of g in Death Valley is 10.417 m/s²
Explanation:
Given that;
acceleration due to gravity at the point is g = 9.8 m/s²
Lets say the acceleration due to gravity at the bottom of Death valley is g'
as the period of the pendulum is decreased by 3.00%
T' = 0.97 T
T is the period of the pendulum at sea level and T' is the period of the pendulum at bottom of Death valley
therefore from the relation
T = 2π√(l/g)
g'/g = T²/T'²
g' = (T²/ (0.97T)²)g
g' = 1.063g
g' = 10.417 m/s²
therefore the value of g in Death Valley is 10.417 m/s²
What is the mechanical advantage of a nail puller where you exert a force 45 cm from the pivot and the nail is 1.8 cm on the other side? What minimum force must you exert to apply a force of 1250 N to the nail?
Answer:
Explanation:
Mechanical Advantage is the ratio of the distance of the input load (Li)from the pivot to the output load applied to the pivot(Lo)
MA = Li/Le
Given;
Li = 45cm
Lo = 1.8cm
MA = 45/1.8
MA = 25
Hence the mechanical advantage is 25
Also MA is expressed in terms of the force ratio which is the ratio of the Load to the effort applied.
MA = Load/Effort
Given
Load = 1250N
MA = 25
Effort = ?
Substitute
25 = 1250/Effort
Effort = 1250/25
Effort = 50N
Hence the minimum force exerted on the load is 50N
The engine of a boat (m = 2280 kg) exerts an
1800 N force northward, while the current
pushes it 1050 N eastward.
What is the magnitude of the acceleration
of the boat?
Answer:
a = 0.9139 [m/s²]
Explanation:
To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
The forces are on two different axes, x & y axes (North and East). In this way, the Pythagorean theorem should be used to determine the total force.
Fx = 1800 [N]
Fy = 1050 [N]
[tex]F = \sqrt{(F_{x} )^{2} +(F_{y} )^{2} } \\F=\sqrt{(1800)^{2} +(1050)^{2} } \\F=2083[N][/tex]
Now using Newton's second law.
ΣF = m*a
where:
F = force = 2083.8 [N] (units of Newtons)
m = mass = 2280 [Kg]
a = acceleration [m/s²]
2083.8 = 2280*a
a = 0.9139 [m/s²]
Is a compound considered a pure substance?
Answer:
It depends on which compound you use carbon dioxide can be while helium will not but if you where to sum it up it would be use because simply most compounds are considered pure substance.
Explanation:
A child sits on a merry-go-round, 1.5 meters from the center. The merry-go-round is turning at a constant rate, and the child is observed to have a radial acceleration of 2.3 m/s2. How long does it take for the merry-go-round to make one revolution
Answer:
5 .07 s .
Explanation:
The child will move on a circle of radius r
r = 1.5 m
Let the velocity of rotation = v
radial acceleration = v² / r
v² / r = 2.3
v² = 2.3 r = 2.3 x 1.5
= 3.45
v = 1.857 m /s
Time of revolution = 2π r / v
= 2 x 3.14 x 1.5 / 1.857
= 5 .07 s .
The merry-go round will take 5.07 s to complete one complete revolution.
Given data:
The distance of child from the center is, r = 1.5 m.
The magnitude of radial acceleration is, [tex]a = 2.3 \;\rm m/s^{2}[/tex].
Since, the child is on merry-go round, which is undergoing a rotational motion. And radial acceleration means that it is under the acceleration, whose value is given as,
[tex]a=\dfrac{v^{2}}{r}\\\\v=\sqrt{a \times r}[/tex]
Here, v is the linear velocity.
Solving as,
[tex]v=\sqrt{2.3 \times 1.5} \\\\v=1.857 \;\rm m/s[/tex]
Now, we to obtain the time taken by merry-go round to complete one revolution. Then the expression for the time taken to complete one revolution is,
[tex]T=\dfrac{2 \pi r}{v}\\\\T=\dfrac{2 \pi \times 1.5}{1.857}\\\\T = 5.07 \;\rm s[/tex]
Thus, we can conclude that the merry-go round will take 5.07 s to complete one revolution.
Learn more about the centripetal acceleration here:
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A 300 g object attached to a horizontal spring moves in simple harmonic motion with a period of 0.340 s. The total mechanical energy of the spring–object system is 3.00 J.
(a) What is the spring constant (in N/m)?
(b) What is the amplitude (in m) of the motion?
(c) What is the percentage change in amplitude of motion if the total energy of the system is increased to 5.00 J?
Answer:
Explanation:
angular velocity ω = 2π / T where T is time period of rotation .
= 2 x 3.14 / .34 = 18.47 rad /s
Total mechanical energy = 1/2 m ω²Α² where A is amplitude .
spring constant = k
[tex]\omega=\sqrt{\frac{k}{m} }[/tex]
m is mass
[tex]\omega^2=\frac{k}{m} }[/tex]
18.47² = k / .3
k = 102.34 N /m
b )
energy = 1/2 m ω²Α²
3 = .5 x 18.47² x A²
A² = .01759
A = .1326
13.26 cm .
c )
If energy becomes 5 J
5 = .5 x 18.47² x A²
A² = .0293
A = .1711
= 17.11 cm
percent increase
= (17.11 - 13.26 )x100 / 13.26
= 29%
The picture below shows a science model made with a balloon, cord, and radiosonde.
Image showing a science model made with a balloon; at the bottom of the balloon is a cord with a radiosonde attached to it.
Which of these is most likely the function of the science model?
To change the density of air
To increase the humidity in air
To reduce the atmospheric pressure
To predict extreme weather conditions
Answer:
Since the person above didn't answer correctly I will, the correct option is (D) this is because the picture shown is of a weather balloon and the purpose of this device is to predict weather and its conditions
Hope this helped! (: Have a nice day
Answer: To predict extreme weather conditions
A radiosonde is a small tool that is put under a balloon filled with either hydrogen or helium. As the radiosonde goes up it measures pressure, temperature, and relative humidity.
When living things use chemical reactions to break down food, some of the energy is transformed into
OA. sound.
OB. heat.
OC. light
OD.waste
waste.
Answer:
OB. Heat
Explanation:
I hope this helped :)
Which statement correctly describes the diferences between positive and negative acceleration
O Positive acceleration describes a change in speed, negative acceleration desxibes no change in speed,
Positive acceleration describes no change in speed, negative acceleration desibes a change in speed,
Positive acceleration describes an increase in speed, negative sexeleration desnibes a decrease in speed
O Positive acceleration describes a decrease in speed, negative sideration describes an increase in sarees
Answer:The answer is this Positive acceleration describes an increase in speed, negative sexeleration desnibes a decrease in speed
Explanation:
Which of these is a base?
HNO3
vinegar
ammonia
HCl
The correct answer is Ammonia
In an experiment, a research collected the following informationabout a solution made from a certain
food. What can we conclude about the food?
• pH = 3.0
• Taste = Sour
A. Acid
B. Base
C. Neutral
D. Salt
Answer:
salt
Explanation:
When water changes from a gas in the atmosphere to a liquid droplet in a cloud, this is known as
Group of answer choices
transpiration
condensation
evaporation
precipitation
Answer:
Condensation
Explanation:
Answer:When water changes from a gas in the atmosphere to a liquid droplet in a cloud, this is known as
Group of answer choices
transpiration
condensation
evaporation
precipitation,←, that one is right
Explanation: so ur answer is precipitation
what energy transfer will a stretched rubber band have when let go
Answer:
when the rubber band is realeased the potential energy is quickly converted to kinetic energy this is equal to one mass of the the rubber band multiplied by its velocity( in meters per second)
If a car traveled 50 meters in 2 seconds, what will the velocity be? (Write the answer with a number, on decimal if needed, then a space and the units, for example 5.7 m/s)
Answer:
The answer is 25 m/sExplanation:
The velocity of the car can be found by using the formula
[tex]v = \frac{d}{t} \\ [/tex]
d is the distance
t is the time taken
From the question we have
[tex]v = \frac{50}{2} \\ [/tex]
We have the final answer as
25 m/sHope this helps you
A carbon ion with 10 electrons and 6 protons would have a charge of ?
Answer:
-4
Explanation:
Electrons are negative while protons are positive.
To find the charge, add the number of protons to the number of electrons.
6+(-10)
6-10
-4 is the charge
How does temperature effect density and the flow of convection currents?
Answer:
Convection
Explanation:
Convection is heat transfer due to a density differential within a fluid. As water's temperature increases in the presence of a heat source, it will become less dense and rise. As it moves up and away from the heat source, it cools and becomes more dense and sinks.
Two hockey players are about to collide on the ice. One player has a mass of
66 kg and is traveling at 1.5 m/s north. The other has a mass of 75 kg and is
traveling at 1.2 m/s south. The system consists of the two tlockey players.
According to the law of conservation of momentum, what is the total
momentum of the system after they collide? Assume the collision is an
elastic collision.
A. 189 kg-m/s south
O B. 9 kg-m/s north
C. 189 kg.m/s north
D. 9 kg m/s south
Answer:
Option B: 9 kg.m/s North
Explanation:
We are told;
One player has a mass of
66 kg and is traveling at 1.5 m/s north.
Thus, velocity is positive since it's acting in the positive direction upwards.
Thus;
m1 = 66 kg
v1 = 1.5 m/s
Also, The other has a mass of 75 kg and is traveling at 1.2 m/s south.
Since it's traveling south, it means that velocity is negative. Thus;
m2 = 75 kg
v2 = -1.2 m/s
From conservation of mass, total momentum is;
m_total = m1•v1 + m2•v2
m_total = (66 × 1.5) + (75 × -1.2)
m_total = 99 - 90
m_total = 9 kg.m/s
This is positive and thus it will be in the direction of the north.
Answer:
9 kg-m/s north
Explanation:
if an object is moving with a velocity of 25m/s, an acceleration of 5m/s and has a travel time of 5s, what is the final velocity of the object?
V = at + V0
where v0 is the initial speed, a is the acceleration and t is the time.
So:
v = 5m/s^2*5s + 25m/s = 50 m/s
1000 kg car takes travels on a circular track having radius 100 m with speed 10 m/s. What is the minimum coefficient of static friction between tires and track needed to keep the car on circular path. *
A- 0.01
B- 0.05
C- 0.1
D- 0.2
Answer:
C. 0.1
Explanation:
A coiled telephone cord forms a spiral with 65.0 turns, a diameter of 1.30 cm, and an unstretched length of 65.5 cm. Determine the inductance of one conductor in the unstretched cord.
Answer:
[tex]L=1.07\ \mu H[/tex]
Explanation:
Given that,
No of turns in a coiled telephone cord is 65
The diameter of the coil, d = 1.3 cm = 0.013 m
Radius, r = 0.0065 m
Unstretched length of the coil, l = 65.5 cm = 0.655 m
We need to find the inductance of one conductor in the unstretched cord. The formula for the inductance is given by :
[tex]L=\dfrac{\mu_oN^2 A}{l}\\\\L=\dfrac{4\pi \times 10^{-7}\times (65)^2\times \pi (0.0065)^2}{0.655 }\\\\L=1.07\times 10^{-6}\ H\\\\L=1.07\ \mu H[/tex]
So, the inductance of one conductor in the unstretched cord is [tex]1.07\ \mu H[/tex].
The first group of planets that are made of rock and closest to the sun
Answer:
A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun
1. A person weighs 155 lbs and is walking 3.1 miles per hour. How much kinetic energy does the person have? (Keep in mind, 1 kg is 2.2 lb, and 1 m/s is 2.24 mi/h.)2. What is the kinetic energy of a 5 g bullet travelling 400 m/s?
3. Is it possible to have a negative KE? Why or why not?
Answer:
Explanation:
Kinetic energy is expressed as;
KE =1/2 mv²
M is the mass
v is the velocity of the object
1) Given
Mass = 155lb
Velocity = 3.1mi/hr
Since 1kg = 2.2lb
x = 155lb
x= 155/2.2
x = 70.45kg
Also
1m/s = 2.24mi/hr
y = 3.1mi/hr
y = 3.1/2.24
y = 1.384m/s
KE = 1/2(70.45)(1.384)²
KE = 0.9577×70.45
KE = 67.47Joules
2) M = 5g =0.005kg
V = 400m/s
KE = 1/2(0.005)400²
KE = 80000×0.005
KE = 400Joules
3} Since a body decelerates (negative acceleration) this mean that the velocity of a body can be a negative value showing that it is possible for a moving body to possess negative kinetic energy.
True or False. A compound is formed when two or more elements are combined to make a
new substance with its own properties.
Anyone?
Answer:
I believe It's true. Since from memory I KNOW a compound is formed when elements are combined chemically.
Answer: correct
Explanation: a compound is 2 or more elements formed to make a completely new thing. For example, water is a compound. Why? Well, water is h20. What is h20? It’s Hydrogen and Oxygen. Oxygen is also a compound. Another example is CO2 (carbon dioxide) it’s made of carbon and oxygen, so it’s a compound! A element is just a pure substance. It’s not made up of other materials. It’s in its purest form.
When a balloon is rubbed on a surface and then touched to hair it will attract the hair, causing it to stick to the balloon. Explain why this happens.
Answer:
electricity
Explanation:
Answer:
This is called static electricity
Explanation:
The reasoning behind this is because the negative electrons in your hair are being transferred to the balloon, then when the balloon is removed it pulls on the hair with an attractive electric force.
Explain the procedures used and data recorded to identify a crystalline mineral based on its properties.
Answer:
By examining its external shape, color, hardness, etc.
Explanation:
A baseball is thrown horizontally with a velocity of 44 m/s. It travels a horizontal distance of 18
m to the plate before it is caught. How long does the ball stay in the air?
A.0.41 sec
B.41 sec
C.4.1 sec
D.4 sec
Answer:
a 0.41
plug number into equation
A horizontal baseball pitch is launched at 44 m/s. The ball will stay for 4.1 sec (approx) in the air. Hence, option C is correct.
What is Velocity?The rate at which an object's position changes when observed from a specific point of view and when measured against a specific unit of time is known as its velocity.
Its SI unit is represented as m/s, and it is a vector quantity, it means that it has both magnitude and direction.
According to the question, the given values are :
Initial Velocity, u = 44 m/s,
Distance travelled, s = 18 m and,
Final velocity, v = 0.
Use equation of motion :
v = u + at
0 = 44 + (-9.8)t
t = 44 / 9.8
t = 4.3 (approx)
Hence, the time for which the ball stay in the air is 4.1 sec (approx).
To get more information about velocity :
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PLZ HELP help me help help
Answer:
matter
Explanation:
Hope I helped :)
Someone help me please it’s urgent
A student builds an electromagnet using a battery, an iron nail, and some insulated wire. The wire is wrapped around the nail 50 times, then connected to the
battery. What changes could the student make to increase the strength of the electromagnet?
1. wrap more wire around the nail
2. increase the voltage of the battery
3. use a switch to turn the electromagnetic on and off
4. increase the size of the nail
A. 1 and 2
B. 2 and 4
C. 1,2 and 4
D. 1,2,and 3
Answer:
a
Explanation:
its right
To increase the electromagnet's strength, the student must enlarge the nail, wrap more wire around the nail, and increase the voltage of the battery. Option c is the correct answer.
How does an electromagnet work?The mechanics of an electromagnet are not overly complicated. It is accomplished by wrapping a length of conductive wire, usually copper, around a metal object.Until electricity is introduced, this appears to be nothing more than a jumbled collection of parts, similar to Frankenstein's monster. An electromagnet, on the other hand, does not require a storm to be activated. A current is introduced and flows through the wire, which can come from a battery or another source of power.As a result of the magnetic field created around the coiled wire, the metal is magnetized as if it were a permanent magnet. Electromagnets are useful because they can be activated and deactivated by closing and opening a circuit.To learn more about electromagnet, refer to
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11. How fast will a pebble be traveling 3 seconds after being dropped? (g = 9.8 m/s2)
A.-9.8 m/s
B.29.4 m/s
C.9.8 m/s2
D.29.4 m/s