Physical Science
Work -
transfer of energy into or out of a system when a force is applied to object that moves it a distance
__________ is the force applied through a distance.
work
A 10-kg object is moving with a speed of 5 m/s at a height of 10 m. The kinetic energy of the object is approximately _____ J.
125
An object has a kinetic energy of 32 J. If the object's speed is doubled, then its new kinetic energy will be ____ J.
128
How much work is required to lift a barbell weighing 1000N from the ground up to a height of 1.5 meters.
1500 J
With what force does a small child push a toy if the toy is pushed 12 meters and 24 J of work is done?
2 N
A 100-kg object is moving with a speed of 2 m/s at a height of 20 m. The kinetic energy of the object is approximately _____ J.
200
What is the work required to raise a 20kg box from the surface of the earth to a height of 10m?
2000 J
A small child pushes a 3Kg toy across the room with a 5 N force a total distance of 6 meters.
30 J
An 8-kg object is moving with a speed of 5 m/s at a height of 4 m. The potential energy of the object is approximately _____ J.
320
A 5-kg object is moving with a speed of 4 m/s at a height of 2 m. The kinetic energy of the object is approximately _____ J.
40
You apply a force of 18N to a dresser and move it 3.0 meters. How much work do you do on the dresser?
54 J
An object will definitely have potential energy if it is _____.
at rest above the ground (a non-zero height) moving above the ground (a non-zero height)
State the Law of Conservation of Energy-
Energy in a closed system must remain constant although the energy can be transformed from one type to another
If an object has potential energy, then its kinetic energy is 0 J.
False
If an object is moving above the ground (at a non-zero height), then it will not have any potential energy.
False
If an object is moving along the ground, then it will not have any kinetic energy.
False
What is meant by the work-energy theorem?
Sum of TMEi + w = TMEf or ΔTME = w
At what point on a roller coaster is the gravitational potential energy (GPE) the lowest?
at the lowest point of the roller coaster
Energy -
ability to cause a change
Potential energy -
energy an object contains due to its position
What force is required to do 100J of work in sliding a box 15m across a level floor?
6.7 N
What are the units for work, kinetic energy, potential energy?
All of these units are Joules which can also me expressed as N•m or kg•m2/s2
What effect does the length of the ramp have upon the distance which a rolling marble drives a paper plow along a level table?
As the length of the ramp increases/decreases the distance the sled slides is unchanged.
A moving 100 kg ball has 3000J of Mechanical Energy. Which of the following is true if you double the mass of the ball?
Both PE & KE Double
The SI unit for energy is the ____.
Joule
The equation for finding kinetic energy-
KE = ½•m•v2 (mass in kg, velocity in m/s)
A softball player is sliding into third base. Once she hits the dirt, the force of friction acts upon her to slow her down as she slides a distance of 1.5 meters across the distance. In this example, friction is doing ______ work upon the player.
Negative
The equation for finding gravitational potential energy-
PE = m•g•h (mass in kg, gravitational acceleration in m/s2, height in m)
Which has more gravitational potential energy: a 50 kg rock 100 m high or a 25 kg table 100 m high?
The rock
Gravitational potential energy is proportional to both mass and height above a reference level.
True
Lowering an object decreases its potential energy.
True
The equation for determining work-
W= F x d
A hot plate converts __________________ to _________________.
electrical, thermal
Kinetic energy -
energy an object contains due to its motion
Mechanical energy -
energy an object contains due to its motion and position
In order to have work done upon an object, there must be a(n) _____ to cause a(n) _______.
force acting upon the object, displacement
Kinetic energy is the energy that an object possesses due to its ____ and potential energy is the energy that an object possesses due to its ____.
motion, position
In which of the following situations do your arms do work on books?
picking up a pile of books from the floor
A car moving at 10 m/s is accelerated to 20 m/s. During this speed change the cars KE will.....
quadruple
To say that energy is" conserved" means that it:
stays the same but can change forms
