5.2 Work done and energy transfer Flashcards
What does it mean if a force is said to do ‘work’?
The force causes an object to be displaced through a distance
What is the equation used to calculate work done? Give appropriate units.
Work done = force x distance
Work done (Joules), Force (Newtons), Distance (Metres)
What distance must be used when calculating work done?
The distance that is moved along the line of action of the force
Under what circumstances is 1 joule of work done?
When a force of 1 newton causes a displacement of 1 metre
How many newton-metres are equal to 1 joule of energy?
1 Nm = 1 J
How much work is being done by a force of 10N over a distance of 5m?
10 x 5 = 50 Nm
= 50 J
What occurs when work is done against frictional forces?
A rise in temperature of the object occurs. Kinetic energy is converted to heat.
Why does air resistance slow down a projectile?
The object does work against the air resistance. Kinetic energy is converted into heat, slowing down the object.
