All about energy review

What is energy?

• The capacity of doing work.

• The electricity supplied by Eskom.

• The calories in the food that we eat.

• The ability to jump up and down.

What is the S.I unit of measurement of energy?

• kiloJoules

• Newtons

• Joules

• Pascals

What is the formula for kinetic energy?

What is the formula for gravitational potential energy?

Which of the following have stored energy?

• Compressed spring

• stretched spring

• book on a table

• the first peak of a rollercoaster

• hot cup of coffee

Answer explanation

A spring at any position other than its neutral on, has stored energy.

the cup of coffee has thermal energy, but no potential energy (until you lift it up to drink)

How much gravitational potential energy does a 100kg (220lb.) skydiver have if they jump from 4000 meters?

• 3920000 J

• 294 J

• 180000 J

• 1225 J

A 6kg cat misjudges a jump and falls 5 meters. How much gravitational potential energy does the cat have? (The cat is fine by the way.)

• 294 J

• 180000 J

• 1225 J

• 3920000 J

What is the kinetic energy of a 1,600kg Mustang travelling at 15 m/s (33mph)

• 180000 J

• 294 J

• 1225 J

• 3920000 J

What is the kinetic energy of a 1,600kg Mustang travelling at 15 m/s (33mph)

• 180000 J

• 294 J

• 1225 J

• 3920000 J

What type of energy is food energy stored in your muscles?

• mechanical

• nuclear

• thermal

• chemical