Kinetic Energy Basics
What two factors determine an object's kinetic energy?
Mass and velocity
What is gravitational potential energy dependent on?
Mass, gravity, and height
Define work in physics.
Work = force × distance
If a force of 10 N moves an object 5 meters, how much work is done?
w = 50 J
What type of energy does a stretched rubber band have?
Elastic Potential Energy
If an object’s velocity doubles, how does its kinetic energy change?
It quadruples
What is the formula for gravitational potential energy?
PE = mgh
What is the unit of work?
Joule (J)
A 3 kg ball is dropped from a height of 4m. What is its potential energy at the top? (Use 9.8 m/s^2)
PE = 117.6 J
What energy conversion occurs when a roller coaster goes from the top of a hill to the bottom?
Potential → Kinetic Energy
Write the formula for kinetic energy.
KE = ½ mv²
If a book is lifted 2 meters with has a weight of 10 N, what is its potential energy?
PE = 20 J
What is power in terms of work?
Power = work/time
If a 5 kg object is moving at 4 m/s, what is its kinetic energy?
KE = 40 J
A pendulum swings back and forth. At what point does it have the most kinetic energy?
At the lowest point of the swing
A ball has the speed of 3 m/s and accumulated 9 J of energy. What is the mass of the ball?
m = 2 kg
A diver stands on a 10m high diving board. If she weighs 500N, what is her potential energy?
PE = 5000 J
What is the unit of power?
Watt (W)
A crane lifts a 100 kg crate 5 meters. How much work is done?
Work = 4,900 J
If you double the mass of a moving car but keep the velocity the same, how does the kinetic energy change?
It doubles
If a car has 2000 J of kinetic energy and its mass is 1000 kg, what is its velocity?
v = 2 m/s
How does increasing height affect potential energy?
It increases proportionally
If you lift a 50N object 2 meters in 5 seconds, what is your power output?
Power = 20W
How many seconds does it take a motor to reach a Power of 300 W when it does 3000 J of work?
Time= 10 seconds
When a pole vaulter runs and then uses the pole to propel themselves over the bar, what energy transformations occur?
Kinetic Energy → Elastic Potential Energy → Gravitational Potential Energy → Kinetic Energy