Part II: Elastic and Inelastic collisions

(1) Check the box labeled “Kinetic Energy”. The simulation provides a number at the top

that represents the total kinetic energy of the two balls before and after the collision.

The slider labeled “Elasticity” is set a 100% as the default setting. Keep the setting. At

100% elasticity a collision is considered “elastic”. Try numerous types of collisions by

changing the parameters for both balls. What can you conclude about the total kinetic

energy before and after the collisions?

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(2) Draw a conclusion concerning elastic collisions with regards to the conservation of

momentum and the conservation of energy. In other words, define an elastic collision.

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(3) Using the slider, change the Elasticity to 0% such that the arrow is directly over the word “inelastic”.

a. Click on the “More Data” button.

b. Manipulate the objects mass, position, and velocity vectors

to match the data below.

c. Calculate the total momentum before the collision (include a proper unit). __________________

d. What is the total kinetic energy before the collision (inclue a proper unit)? __________________

e. Press the play button and pause the simulation after the collision. Calculate the total momentum

after the collision (include a proper unit). _____________________

f. What is the total kinetic energy after the collision (include a proper unit)? __________________

(4) What can you conclude about the law of conservation of momentum for elastic and inelastic collisions?

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(5) What can you conclude about the law of conservation of energy for elastic and inelastic collisions?

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(6) Try various other inelastic (< 100% Elasticity) collisions by manipulating the parameters. Based upon

your observations, define inelastic collisions.

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(7) A 50% inelastic collision occurs between a 0.7 kg ball moving to the left with a velocity of 1.8 m/s and a

1.6 kg ball moving to the right at 0.5 m/s. After the collision, the 1.6 kg ball moves to the left with a

velocity of 0.55 m/s. The formula for kinetic energy of an object is given by: .

a. Calculate the kinetic energy for each ball before the collision. Show all your work.

b. Determine the total kinetic energy before the collision (include a proper unit). _______________

c. Calculate the kinetic energy of each ball after the collision. Show all your work.

d. Determine the total kinetic energy after the collision (include a proper unit). ________________

e. Calculate the change in kinetic energy during the collision ( ). ________________________

f. Suggest a reason for why the total kinetic energy before and after an inelastic collision is not the

same. _________________________________________________________________________

An elastic collision is a collision in which energy is conserved.

The law of conservation of momentum holds for both types of collisions -- elastic and inelastic.

The law of conservation of energy holds for elastic collisions but does not hold for inelastic collisions.

Inelastic collisions are collisions in which energy is not conserved.

Energy is lost in the collision to light, heat, or sound.