Chapter 7 Work, Energy and Power

Question 1

What is work?

Answer 1

A product of Force and displacement in the direction of force

Question 2

What is the S.I unit for work?

Answer 2

Joules ( J )

Question 3

How many joules is a kilojoule/Megajoule?

Answer 3

kJ 1000
Mj 1000000

Question 4

What are 2 other physical quantities are measured in newton metre?

Answer 4

Moment of Force
Energy

Question 5

What is the formula for calculating work?

Answer 5

W = FxS

Question 6

What is energy?

Answer 6

The ability to do work ( If 1N is used to move an object over a distance of 1m in the direction of force, 1 J of energy is used )

Question 7

What is power?

Answer 7

The rate of doing work?

Question 8

Formula for power?

Answer 8

Time Taken

Question 9

What is the S.I unit for power?

Answer 9

Watt

Question 10

What is gravitational potential energy?

Answer 10

Work done to life an object to a height from the earth’s surface

Question 11

Formula for gravitational potential energy?

Answer 11

mgh
(mass = kg ) ( Gravitational accel in m s-2 )
( height = m )

Question 12

What is elastic potential energy?

Answer 12

Work done to compress or stretch an elastic material over a displacement of X from the position of equilibrium

Question 13

Formula for elastic potential energy?

Answer 13

1/2 F ( force <N> ) x ( Displacement from equilibrium position <m> )</m></N>

Question 14

What is kinetic energy?

Answer 14

Energy possessed by a moving object

Question 15

What is the formula for kinetic energy?

Answer 15

1/2m ( mass <kg> ) v2 ( velocity <m> )</m></kg>

Question 16

What is stated in the principle of conservation of energy?

Answer 16

Energy cannot be destroyed or created but can be converted from one form to another

Question 17

What is an example of an oscillating system?

Answer 17

Heartbeat
Pendulum Clock