KE
What two things determine an object's kinetic energy?
Mass and velocity/speed
What three things determine gravitational potential energy?
HAM
A lamp changes electrical energy mainly into what type of energy?
Light energy
According to the Law of Conservation of Energy, energy cannot be created or ______.
Destroyed
Which has more kinetic energy: a parked truck or a moving bicycle?
Moving bicycle, because the parked truck has 0 KE
A 2 kg ball moves at 4 m/s. What is its kinetic energy?
16j
What number do we normally use for acceleration due to gravity on Earth?
9.8 m/s
What is the main energy transformation in a toaster?
electrical to thermal
A system starts with 700 J of energy. If 200 J is transferred to the surroundings, how much remains in the system?
500 j
If an object's speed increases while its mass stays the same, what happens to its kinetic energy?
It increases
A 5 kg object moves at 6 m/s. Calculate its kinetic energy.
90j
A 10 kg object is sitting 5 m above the ground. What is its GPE?
490j
A battery-powered flashlight changes energy through what sequence?
Chemical → electrical → light
A machine receives 1,000 J of energy. It transfers 250 J as thermal energy and 150 J as sound. How much energy remains for its main output?
600 j
Two identical balls are placed at heights of 2 m and 8 m. Which has more GPE?
The ball at 8m
An object has 100 J of kinetic energy and a mass of 2 kg. What is its velocity?
9.8 m/s
A 20 kg object has 1,960 J of GPE. How high is it?
10m
A remote control uses a battery to send an infrared signal to a TV. Identify the energy transformation in the remote.
Chemical → electrical → electromagnetic/light
A roller coaster has 2,000 J of GPE at the top. Ignoring friction, how much KE could it have at the bottom?
2000 j
A 4 kg object is moving at 10 m/s. What is its kinetic energy?
200 j
A stone has 324 J of kinetic energy and is moving at 9 m/s. What is its mass?
8kg
An object sitting 4 m high has 784 J of GPE. What is its mass?
20 kg
A roller coaster begins at the top of a hill and travels downward. Describe the main energy transformation.
Gravitational potential → kinetic
A system begins with 1,500 J. It transfers 375 J as thermal energy, 125 J as sound, and 200 J as light. How much energy remains?
800 j
A 10 kg object is sitting 20 m above the ground. It falls. Ignoring air resistance, what happens to its GPE and KE as it falls?
GPE decreases while KE increases; energy is transformed from GPE to KE