Calculating Potential Energy and Kinetic Energy

What is the formula for calculating kinetic energy?

• KE = 1/2 x m x v^2

• KE = mgh

• KE = m x v^2

• KE = 1/2 mgh

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Understanding

A 3 kg cow is moving at a velocity of 4 m/s. What is its kinetic energy?

• 24 joules

• 12 joules

• 48 joules

• 6 joules

Answer explanation

• ✏️ KE = ½ × 3 × 2²

• = ½ × 3 × 4

• = 6 J

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Applying

Potential energy is the energy stored in an object due to its ___ or condition.

• speed
• mass
• temperature
• position

If a 2 kg book is placed on a shelf 10 meters high, what is its potential energy? (Use g = 9.8 m/s²)

• 58.8 joules

• 294 joules

• 196 joules

• 39.2 joules

Answer explanation

✏️ PE = 2 × 9.8 × 10 = 196 J

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Applying

True or false: A parked car has kinetic energy.

• False

• True

Answer explanation

1. ✏️ A parked car is not moving, so it has no kinetic energy. It may have potential energy depending on its position.

Tags

Understanding

A boy and his dog are running on the beach.

• The white dog has a mass of 10 kg

• The black dog has a mass of 20 kg

• The boy has a mass of 40 kg

• They are all running at the same speed of 3 m/s²

Determine the kinetic energy for each.

• 180 J

• Boy

• 45 J

• White Dog

• 90 J

• Black Dog

Graph the information you calculated as a bar graph to show how mass and kinetic energy are related.

Use black for the black dog (90 J)

Use yellow for the white dog (45J)

Use red for the boy (180 J)