Work, Power, Energy

What are the units for Work?

• Joules (J) or Newton (N)

• Joules (J) or Newton.meters (N.m)

• Pascal (P) or Newton (N)

• Pascal (P) or Joules (J)

 When a force (F) is applied to an object and causes the location of the point of application to displace in space (Δd). Therefore, what is the formula for Work?

• W   =  F / Δd

• W   =  F x Δd

• W   =  Δd - F

• W   =  F x distance

A force of 1500 N is applied during the drive off from a sprint start. The centre of mass moves a distance 0.4 m. What work is done?

• 1200 J

• 1500 J

• 3750 J

• 600 J

Energy is the capacity to do work. There are different forms of energy. What is the example of Potential Energy?

• Holding a weight above the head

• Speed of sprint runner

• Stretching spring weights

• Holding a weight below the head

Power is defined as...

• the capacity to do work

• the location of the point of application to displace in space

• no energy change then total mechanical energy remains constant

• the rate at which work is being done

= ½ m · v2

describes which type of energy?

• potential energy

• linear kinetic energy

• elastic energy

• strain energy

ES = ½ k · Δx2

The above is the formula for Elastic Energy. What is an example of an elastic energy?

• holding a weight above the head

• speed of sprint runner

• stretching spring weights

• holding a weight above the head

i.Calculate the potential energy of an athlete of 73kg that is 1.5m above the ground.

• 3630 J

• 1074.2 J

• 1045.4 J

• 7300 J

A long jumper with a mass of 60 kg approaches the take-off board with a velocity of 11m.s-1. What is their linear kinetic energy?

• 3630 J

• 1047.2 J

• 1045.4 J

• 3330 J

Will work done be easier or harder for a weight lifter with a shorter stature?

• easier

• harder