[FWE] force, work done and energy

Question 1

what is energy?

Answer 1

energy is the capacity to do work

Question 2

what is potential energy?

Answer 2

potential energy is the stored energy due to an object’s position or condition

Question 3

what is chemical potential energy?

Answer 3

chemical potential energy is stored in fuels and can be released through chemical reactions

Question 4

what is elastic potential energy?

Answer 4

elastic potential energy is the energy an object has when stretched or compressed

Question 5

what is gravitational potential energy?

Answer 5

it is the energy an object has due to it position, it is affected by mass and height

Question 6

what is kinetic energy?

Answer 6

kinetic energy is energy due to an object’s motion, depending on mass and speed

Question 7

in what forms can energy be transferred?

Answer 7

energy can be transferred as heat, light, sound or electrical energy

Question 8

what is the principle of conservation of energy

Answer 8

energy cannot be created or destroyed but can be transferred or converted between forms

Question 9

what are some examples of energy resources?

Answer 9

fossil fuels, solar energy wind energy, hydroelectric energy, geothermal energy, biofuels and nuclear energy

Question 10

what is a force?

Answer 10

a force is either a push or a pull that can change an object’s shape, size, speed or direction

Question 11

what units are used to measure force?

Answer 11

the nSI unit for force is Newton(N)

Question 12

what is elastic force?

Answer 12

elastic force returns a stretched or compressed elastic object to its original shape

Question 13

what is friction?

Answer 13

friction opposes motion between surfaces in contact

Question 14

what are the seven ways friction can be reduced?

Answer 14

friction can reduced by using smooth surfaces, wheels, rollers, ball bearings, lubricants, air cushions, or adopting streamlined shapes

Question 15

what is a magnetic force?

Answer 15

magnetic force acts between two magnetic poles of a magnet

Question 16

what is weight?

Answer 16

weight is the gravitational force acting on an object

Question 17

what is mass?

Answer 17

mass is the amount of matter in a body

Question 18

what’s the difference between weight and mass?

Answer 18

mass only has magnitude, while weight has both magnitude and direction

Question 19

what is electrostatic force?

Answer 19

electrostatic force is the force that acts between two charged particles

Question 20

how can a force affect an object?

Answer 20

it can change the object’s
- speed
- direction
- cause a turning effect
- exert pressure

Question 21

what is the resultant or net force?

Answer 21

if forces are balanced, there is no net force. if it is unbalanced, there is a net force

Question 22

what is pressure and its SI?

Answer 22

pressure is defined as force per unit area
its SI is Pascal (Pa)

Question 23

how is work done defined?

Answer 23

work done is when a force applied to an object causes it to move in the direction of the force

Question 24

what units are used to measure work done

Answer 24

SI unit: joule (J)

Question 25

what conditions are required for work to be done?

Answer 25

• a force must act on the object
• the object must move
• the movement must be in the direction of the force

Question 26

how is work done calculated?

Answer 26

workdone = force x distance moved in the direction of the force

Question 27

what are some factors to consider when calculating work done?

Answer 27

always check for changes in KE, GOE and work done against resistance/friction