Energy review

Energy review

Multiple Choice

The following image BEST demonstrates an example of thermal energy?

Multiple Choice

The following image BEST demonstrates an example of kinetic energy?

Multiple Choice

The following image BEST demonstrates an example of potential energy?

kinetic energy

• energy due to motion

• measured in joules

• as you increase your speed, your kinetic energy grows much faster

•  $KE\ =\ \frac{1}{2}\cdot m\cdot v^2$  

• (be prepared to do a calculation on the next slide. have a calculator ready)

Multiple Choice

An 800kg truck is traveling at 14 m/s down the road. What is its kinetic energy?

• 11,200 joules

• 5,600 joules

• 78,400 joules

• 57 joules

Multiple Choice

A 0.2kg toy car has 17 joules of kinetic energy. How fast is it going?

• 13 m/s

• 85 m/s

• 3.4 m/s

• 1.7 m/s

Potential energy

• energy that is stored and can be converted to other useful forms of energy (like kinetic energy)

• Can use gravity to store energy for an object - depends on its mass, and its relative height.

•  $PE\ =\ m\cdot g\cdot h$  

• "g" is the gravitational field you are in (9.8N/kg on earth)

Multiple Choice

A 50kg skydiver is 3,000 meters above the ground. What is their potential energy?

• 15,000 joules

• 60 joules

• 150,000 joules

• 1,470,000 joules

Multiple Choice

A 0.89kg box is siting on a shelf, and has 20 joules of potential energy. How tall is the shelf

• 2.3 meters

• 22.5 meters

• 17.8 meters

• 1.8 meters

Multiple Choice

A bike rider starts out from rest on a flat road. The biker gradually accelerates to a speed of 12 mph.

What is happening to the biker's kinetic energy?

• increasing

• decreasing

• staying the same

Multiple Choice

A bike rider starts out from rest on a flat road. The biker gradually accelerates to a speed of 12 mph.

What is happening to the biker's potential energy?

• increasing

• decreasing

• staying the same

Multiple Choice

The bike rider continues at a constant speed of 12 mph down the flat road.

What is happening to the biker's kinetic energy?

• increasing

• decreasing

• staying the same

Multiple Choice

The bike rider continues at a constant speed of 12 mph down the flat road.

What is happening to the biker's potential energy?

• increasing

• decreasing

• staying the same

Multiple Choice

The bike rider starts biking up a small hill, and is able to maintain a constant speed of 12 mph.

What is happening to the biker's kinetic energy?

• increasing

• decreasing

• staying the same

Multiple Choice

The bike rider starts biking up a small hill, and is able to maintain a constant speed of 12 mph.

What is happening to the biker's potential energy?

• increasing

• decreasing

• staying the same

Multiple Choice

The biker goes over the top of the hill and is now going down the other side. The biker is going faster and faster.

What is happening to the biker's kinetic energy?

• increasing

• decreasing

• staying the same

Multiple Choice

The biker goes over the top of the hill and is now going down the other side. The biker is going faster and faster.

What is happening to the biker's potential energy?

• increasing

• decreasing

• staying the same