T5 work done and energy transfers

Question 1

what does it mean if a force is said to do “work”

Answer 1

the force causes an object to be displaced through a distance

Question 2

equation used to calculate work done

Answer 2

work done = force x distance

work done (joules), force (newtons), distance (metres)

Question 3

what distance must be used when calculating work done

Answer 3

it must be the distance that is moved along the line of action of the force

Question 4

under what circumstance is 1 joule of work done

Answer 4

when a force of 1 newton causes a displacement of 1 metre

Question 5

how many Newton-metres are equal to 1 joule of energy

Answer 5

1 Nm = 1 J

Question 6

what occurs when work is done against frictional forces

Answer 6

• a rise in temperature of the object occurs

- kinetic energy is converted to heat

Question 7

why does air resistance slow down a projectile

Answer 7

• the object does work against the air resistance

- kinetic energy is converted in to heat, slowing down the object