P5 - Forces 2 Work Done and Energy Transfer Flashcards
1
Q
What does it mean if a force is said to do ‘work’
A
The force causes an object to be displaced through a distance
2
Q
What is the equation to calculate work done ? Give appropriate units
A
Work done = Force x Distance
Work done (joules) , Force (Newtons) , Diatance (metres)
3
Q
What distance must be used when calculating work done ?
A
The distance must be in the line of action of the force
4
Q
Under what circumstance is 1 joule of work done ?
A
When a force of 1 Newton causes a displacement of 1 metre
5
Q
How many Newton-metres are equal to 1 joule of energy ?
A
1 Nm = 1 J
6
Q
What occurs when work is done against frictional forces?
A
- A rise in temperature of the object occurs
- Kinetic energy is converted into heat
7
Q
Why does air resistance slow down a projectile ?
A
- the object does work against the air resistance
- Kinetic energy is converted in to heat , slowing down the object
