Question

A 1,000-W motor powers a hoist used to lift cars at a service station.

(a) How much time would it take to raise a 1,050-kg car 2 m?
s

(b) If the original motor is replaced with one rated at 3,000 W, how long would it take to complete this task?
s

Answer 1

(a) 41.16 second

(b) 20.58 seconds

Step-by-step explanation:

(a) Power = Energy /time

=> Energy = mgh = 2100*9.8*2 = 41160 J

=> 1000 = 41160 /t

=> t = 41.16 second

(b) 2000 = 41160/t

=>t = 41.16/2 = 20.58 seconds