Question

Barbara argues that simple machines like levers and pulleys reduce the amount of work needed to get things done. Clarice argues that machines don’t decrease work - they decrease force.
Who is right

Answer 1

Clarice is right — in the physics sense.

Why: Work is defined as W = F · d (force times distance). An ideal simple machine (no friction) does not change the total work required to move an object; it trades force for distance. For example, to lift a 50 kg mass 1 m you must do about 490 J of work (mgh). If a machine gives you a mechanical advantage of 10, the input force is 49 N but you must pull 10 m, so the input work is still 49 N × 10 m = 490 J.

More formally for an ideal machine: F_in · d_in = F_out · d_out. Real machines have friction, so input work > useful output work (you actually do more work than the ideal output), never less.

Caveat: In everyday language “doing less work” often means “less effort” (smaller force), so Barbara’s statement makes sense colloquially — machines reduce the force you must exert — but they don’t reduce the physical work required to change the object’s energy.