# Physics Home Experiment-Conservation of energy and momentum

Home Experiment 1

PURPOSE

This experiment was designed to understand and confirm the conservation of energy and the conservation of momentum.

Part I - Conservation of Energy

Equipment Setup

Slotted plastic ruler

Steel ball bearing

Put the ruler at a shallow incline on a table or a chair. Your setup should look something like this:

Procedure

First, roll the ball down from the top inclined ruler and measure the horizontal

distance the ball travels before it hits the floor. You probably should do this at least

5 times to get a good, average distance.

Analyzing the Data

1. Using projectile motion equations, determine the speed of the ball the instant that it leaves the table. Show your work and value below:

2. Now measure the vertical height of the slotted ruler (use another ruler?).

3. Now compare the potential energy of the ball prior to its release to the kinetic energy of the ball just as it leaves the table. (You don't know the mass of the ball, if you do this right it should cancel out). Show your work and reasoning below:

Part II? Conservation of Momentum

Procedure

Now place a second ball in the slot of the ruler at the edge of the table. Now, when the first ball rolls down the incline, it collides head on with the second ball. The second ball now becomes the projectile.

1. Again, perform the collision about 5 times and determine the speed at which the ball is projected off the table. Show your work below:

2. Using the conservation of energy (like you performed in the first part) to determine the speed of the first ball at the bottom of the ruler just before it hits the second ball. Show your work below:

3. With the balls exactly the same, the conservation of momentum dictates that momentum of the first ball is transferred to the second ball. Using the data you've gathered, can you confirm or deny this statement? Show your work below:

4. How could this experiment be improved to produce better data collection and analysis?

See attachment for image.

#### Solution Preview

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Conversation of Energy

Part I - Conservation of Energy

Procedure

Put the ruler at a shallow incline on a table or a chair. Your setup should look something like this:

First, roll the ball down from the top inclined ruler and measure the horizontal

distance the ball travels before it hits the floor. You probably should do this at least

5 times to get a good, average distance.

1. Using projectile motion equations, determine the speed of the ball the instant that it leaves the table. Show your work and value below:

Let s be the horizontal distance traveled by the ball before it hits the floor.

Let h be the height of the table from the floor.

Let u be the speed of the ball when it leaves the table.

Let H be the height of the incline.

Use s = ut + 1/2 a t^2 for the motion of the ball.

Horizontally: s = u * t + 0 = ut

Vertically: h = 0 + 1/2 g t^2 = 1/2 g t^2

Solving these two equations, we get

u = s * sqrt(g/2h) --------------------------------- ...

#### Solution Summary

This experiment was designed to understand and confirm the conservation of energy and the conservation of momentum. Experiment was performed at home and the results and analysis are presented.