Two identical machines operate for the same 5.0 s interval
PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
Two identical machines operate for the same 5.0 s interval.
• Machine X: power increases uniformly from 0 W at t=0 to 240 W at t=5.0 s.
• Machine Y: power remains constant at 100 W throughout the interval.
Which statement correctly compares the work done by the two machines during the interval?
(a) Machine Y does more work because its power output is never zero, while Machine X’s is zero at the start.
(b) Machine X does more work because its average power (120\,W) is greater than the constant 100\,W of Machine Y.
(c) Machine X does more work because its maximum (final) power is greater than that of Machine Y.
(d) Machine Y does more work because the energy it delivers equals the area of a rectangle, whereas Machine X’s energy equals the area of a triangle.