Question

If I do 100 Joules of work to lift my backpack, then half of everything falls out so that I can lift it using half the force, how much work will I do to lift it the same distance?

Answer 1

Answer: If you did 100 Joules of work to lift your backpack, then the work you did is equal to the force applied multiplied by the distance lifted. Let's say you lifted the backpack a distance of d meters with a force of F Newtons. Then:

100 J = F x d

Now, if half of everything falls out of your backpack, the force required to lift the backpack will be reduced by half, so the new force required will be F/2. The distance lifted remains the same. So the work done to lift the backpack using half the force is:

Work = (Force x Distance) / 2

= (F x d) / 2

But we know that F x d = 100 J, so we can substitute this in the equation above:

Work = (F x d) / 2

= 100 J / 2

= 50 J

Therefore, the work you will do to lift your backpack the same distance with half the force is 50 Joules.

Explanation: