Laws of Conservation and Physics Problems

Conservation of Energy for Gravitational and Spring

a. Conservation energy for gravitational and spring

 

b. Conservation of momentum

 

c. Conservation of kinetic energy

 

1. Which has more momentum, a 1000 kg car moving 1 m/s or a 70 kg person sprinting at 8 m/s?

 

2. A tennis ball may leave a top player’s racket on the serve with a speed of 65.0 m/s. If the ball’s mass m= is 0.0600 kg and it is in contact with the racket for t=0.0300 s, what is the average force exerted on the ball?

 

3. A 1500 kg car traveling at 15 m/s collides with a 500 kg moose which is at rest. If the moose is knocked backward at 20 m/s, what happens to the car?

 

4. A 1500 kg car traveling 5.0 m/s collides head on with a 3000 kg truck traveling 7.0 m/s in the opposite direction. If the bumpers lock (the collision is inelastic),

 

a) what is the velocity of the two vehicles together immediately following the collision?

 

b) what is the magnitude of the change in velocity experienced by the driver of each car during the collision?

 

c) A 50 kg gorilla is sitting on the limb of tree 4 meters above the ground.

 

6. Find the gravitational potential energy of the gorilla sitting on in the tree.

 

a. Gorilla through a coconut of mass 3kg down with an initial velocity of 6m/s what is the total kinetic energy of the coconut right before it hits the ground

 

b. The gorilla jumps down from the tree limbs to ground. Use the conservation of energy to find the velocity of the gorilla just before hitting the ground.

 

c. Use the conservation of energy to calculate the potential, kinetic energy, and mechanical energy of the ball of mass m=3.2kg released from h=4 meter at each given point on the figure.

5. What is potential energy, kinetic energy and total mechanical energy at:

1. Point 1
2. Point 2
3. Point 3
4. Point 4

6. Kinetic and spring potential energy problem: A block (m=5.0kg) is pushed against a spring that is compressed a distance of x=10.0cm. The block is then released and travels up a frictionless inclined surface see the figure.

 

a. How much potential energy is stored in the spring?

 

b. After the block leaves the spring, what is the kinetic energy of the spring,

 

c. Find the velocity of the block right after the block leaves the spring

 

d. Find the maximum height of h of the block if the spring constant k= 100 N/m.

 

7. Ahmad stretches a spring for x=40.0cm from its resting position. The spring constant is k= 20.0 N/m.

 

a. How much spring potential energy is stored in the spring?

 

b. What is the restoring force applied by the spring?

 

8. Elastic potential energy

 

a. Elastic potential energy stored in the band if it is pulled back about d=0.5 meter and has spring constant of k =50 N/m

 

b. Kinetic energy of a rock of mass m= 50gram after it is shot by the band

 

c. What is the velocity of the rock right after it is released from the band?