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 × distance
work done (joules), force (newtons), distance (meters)
What distance must be used when calculating work done?
It must be the distance that is moved along the line of action of the force.
Under what circumstance is 1 joule of work done?
When a force of 1 Newton causes a displacement of 1 meter.
How many Newton-meters are equal to 1 joule of energy?
1 Nm = 1 J
How much work is done by the force acting on the object in the picture over a distance of 5 meters?
10 × 5 = 50 Nm
= 50 J
What occurs when work is done against frictional forces?
A rise in the 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.