Conservation of Mechanical Energy Review:

Name:______Date:______

ALL Q’S WORTH 4PTS

Answer the following questions using: A) KE (Kinetic Energy) B) PEe(Elastic Potential Energy) . C) PEg( Gravitational Potential Energy) D) Frictional Losses (heat)

There may be multiple answers and assume no frictional losses unless the question implies there are.

1)______: As the notorious boarder cruzes at the bottom of a half pipe, what type of energy does she have?

2)______: If the same boarder hit the half pipe straight on and reached her maximum height such that she is not moving at her maximum height, what type of energy does she have at her maximum height.

3)______: If the same skate boarder hit the half pipe at an angle so that when she reached her maximum height she is still moving sideways, what type(s) of energy(s) does she have?

4)______: When the boarder is descending to the bottom of the ramp, what type of energies does the mechanical energy consist of?

5)______: The boarder approaches the other side of the half pipe and does not go as high as the last time. What type of energy did this missing mechanical energy of system turn into.

6)______: What type of energies makes up the skateboarder’s ME?.

PROBLEMS:

Use the diagram above for the following calculations:

1)What is the total ME of the system:

2)Find the initial height of the snow boarder if his mass is 80 kg:

3)Find how high the snowboarder is when she has a gravitational PE of 15,000J

4)Find how fast she is moving when she has a KE of 35,000J:

5)How Fast is the snowboarder when he is at ground level:

6)Find how far the snowboarder would slide if he had a frictional force of 40N while traveling on the ground. Hint: Use work(energy) = force x distance

7)In the following spring mass system, the block is moving back and forth through its equilibrium position (location where the spring is relaxed). If the maximum displacement the spring makes is .8m, find the following: (+3 each)

a)Potential energy stored at .8m if the spring constant equals 200 n/m:

b)Mechanical energy of the system:

c)How fast the block is moving when it passes the equilibrium position (where x=0):

d)How fast is the block moving at the .4m marker:

8)Find the speed of a 100kg cart that is pushed for 30m with a force of 50N.

9)Describe why it is dangerous to speed in terms of kinetic energy.

10) As you walk down the road you are using energy. Describe every step that this energy had to take to make it to you.