Energy Losses in a Bouncing Ball
Name ______
______
______
Purpose:
To investigate the relationship between the height a ball bounces to and the energy it loses.
Background:
Some formulas you may need for this lab and the questions at the end include:
g = 9.8-m/s2
The mechanical energy of an object is the sum of the potential energy and the kinetic energy:
You may also need to convert some units:
To convert from grams (g) to kilograms (kg):
To convert from centimeters (cm) to meters (m):
Background Questions:
1)What is gravitational potential energy? How does height affect this?
2)What is kinetic energy? How does speed affect this?
3)What is mechanical energy? How do you find mechanical energy?
4)When a ball falls, what happens to its potential energy? What happens to its kinetic energy?
5)When a ball falls and bounces, will it bounce to the same height it was dropped from? Why do you think this happens?
Materials:
Meter StickBallScale(Shared)
Procedure:
1)Measure the mass of your ball at the scale. Be sure to record this value below. Be sure the mass is in kg.
Mass of ball: ______
2)You are going to drop a ball from a height of 1-m. Calculate the potential energy of the ball at a height of 1-m. Record this valuebelow. Be sure to include its units.
Potential Energy of the ball @ 1-m: ______
3)Just before you drop the ball from a height of 1-m, what is its kinetic energy? {Hint: Is the ball moving just before you drop it?} Record this value below. Be sure to include its units.
Kinetic Energy of the ball @ 1-m: ______
4)Calculate the mechanical energy of the ball just befor you drop the ball from a height of 1-m. Record this value below. Be sure to include units.
Mechanical Energy of the ball @ 1-m: ______
5)Drop the ball from a height of 1-m and observe its fall.
a)What happens to the ball’s potential energy as it falls? Why?
b)What happens to the ball’s kinetic energy as it falls? Why?
6)Based on your answers to #5, determine the potential energy, the kinetic energy and the mechanical energy of the ball just before it hits the table. Record these values below. Be sure to include units.
Potential Energy of the ball just before it hits the table: ______
Kinetic Energy of the ball just before it hits the table: ______
Mechanical Energy of the ball just before it hits the table: ______
7)Drop the ball from a height of 1.0-m again and measure the height it bounces. Do this three times and take an average. You will use this average height for the analyisis of your data. Record these values in the table below. Be sure your heights are in meters.Measure these heights to the bottom of the ball.
Bounce Height (m)Trial 1 / Trial 2 / Trial 3 / Average Height
8)As the ball bounces back up what happens to its potential energy and its kinetic energy? Why?
9)Calculate the potential energy of the ball, the kinetic enegry of the ball and the mechanical energy of the ball at the bounce height. Use the average height. Record these values below. Be sure to include units.
Potential Energy of the ball @ the average bounce height: ______
Kinetic Energy of the ball @ the average bounce height: ______
Mechanical Energy of the ball @ the average bounce height: ______
Analysis:
Do the following calculations and record your results in the diagram. Then use the diagram to help you answer the questions.
1)Record the mass of the ball, thebounce height of the ball, the potential, kinetic and mechanical energy at 1-m, just before the ball hits the table and at the bounce height in the diagram on the next page.
2)Calculate the potential energy, kinetic energy and mechanical energy just after the ball bounces. Record these values in the proper place on the diagram.
3)Calculate the amount of energy “lost” during the bounce for the ball and record this in the diagram.
4)This energy isn’t really “lost”, it is just transferred to another form or forms of energy. Where did this “lost” energy go?
Bouncing Ball Diagram