Conceptual Ideas
Momentum
Graphs
Work Out
Energy
100
What law states that total energy will not change in an isolated system?
Law of conservation of energy
100
A car with mass 1500kg drives at 20m/s. How much momentum does the car have?
30,000 km/s
100
A pendulum is released from rest from a height of x meters, the energy of the pendulum during its travel is shown in the graph below.
What type of energy is displayed on the graph for:
a.) The Red Line
b.) The Blue Line
c.) The Green Line
a.) Kinetic Energy
b.) Potential Energy
c.) Total Energy
100
A box is pushed by a force of 5N across a distance of 3m. How much work is done on the box?
15 J
100
A rock with mass 2kg is on a cliff 50m off of the ground. How much potential energy does it have?
1,000 J
200
An object that has a small mass, an object with a medium sized mass, and an object that has a large mass have the same momentum. Which object has the largest kinetic energy?
Object with a small mass
200
A 0.2 kg baseball is pitched at 30 m/s and is hit by a bat, changing its direction and speed to 40 m/s in the opposite direction. Calculate the impulse exerted on the baseball by the bat.
-14 Ns
200
A box has an increasing force applied to it until time t, when the force becomes constant. Below is the graph of the box's displacement in relation to time. What is the work done by the force?
240 Nm
200
A car with a mass of 1,000 kg accelerates from rest to a speed of 20 m/s. Calculate the work done on the car to reach this speed.
200,000 J
200
A rock with a mass of 5 kg is lifted to a height of 12 m above the ground on a mountain trail. What is the gravitational potential energy of the rock relative to the ground?
600 J
300
Explain in terms of impulse how padding reduces forces in a collision.
Padding elongates the time of the collision, which reduces the force on the object in the collision.
300
A 2 kg cart moving at 4 m/s collides elastically with a 3 kg cart at rest. After the collision, the 2 kg cart moves at 2 m/s. Calculate the final velocity of the 3 kg cart after the collision.
1.33 m/s
300
The graph below depicts the momentum of a tennis ball as time passes. What is the net force on the tennis ball between 5 and 10 seconds?
1 N
300
A spring with a spring constant of 200 N/m is compressed by 0.5 meters from its equilibrium position. Calculate the work done in compressing the spring.
25 J
300
A spring in a mechanical toy has a spring constant of 250 N/m. The spring is compressed by 0.2 meters as the toy is being set up for play. How much potential energy is stored in the spring when it is compressed?
300,000 J
400
A boy stands on the back of a rowboat and dives into the water. Explain why, according to conservation of momentum, the boat moves in the opposite direction of the boy.
Initially, the boy-boat system has no momentum. When jumping into the water, the boy gains momentum therefore the boat needs to gain momentum in the other direction to keep the total momentum as 0.
400
A 5 kg truck moving at 10 m/s collides with a 3 kg car moving at 2 m/s in the same direction. After the collision, the two vehicles stick together and move as a single object. Calculate the final velocity of the combined truck and car system.
7 m/s
400
A spring is stretched, increasing its elastic potential energy as shown in the graph below. What is the spring constant of the stretched spring?
17.3 N/m
400
A motor operates at a constant power output of 500 W for 10 seconds before shutting off. What is the total work done by the motor?
5,000 J
400
On a rollercoaster, a car initially has 50,000J of potential energy at the top. By the time the car reaches the bottom, the work done by friction is 20,000J. How much kinetic energy does the car have at the bottom of the rollercoaster.
30,000 J
500
A rock of mass M is sitting on the top of a cliff of height H. Just before the rock reaches the bottom it has a velocity V. The mass of the rock is doubled and the height of the cliff is doubled, what is the new velocity in terms of V?
~1.41V
500
A 10 kg object at rest explodes into two pieces. One piece has a mass of 4 kg and moves at 6 m/s to the right. The other piece moves to the left. Calculate the velocity of the second piece after the explosion.
-4 m/s (4 m/s to the left)
500
D
500
A sled with a mass of 30 kg is pulled across a horizontal surface with a constant velocity. The frictional force acting on the sled is 150 N. Calculate the work done by friction over a distance of 100 meters.
−15,000 J
500
A pendulum with a bob of mass 2 kg is released from a height of 5 m. Assume there is no air resistance. What is the total mechanical energy of the system at any point during its swing?
100 J