Work required and power being used.

Question

Find the work required to lift a mass of 5 tonnes to a height of 30m.  If this is done in 2 minutes, what power is being used?

Answer 1

Hey David,

 

1 ton = 1000kg  --> 5 ton = 5000kg

 

w = mgh (mass) (gravity) (height)

              (mass) (acceleration) (displacement)

 

5000 * 9.8 * 30 = 1470000 J  (Joules)

1.47 x 10⁶ J  (work done)

 

Power = (work) / (time) = (Joule) / (second) = (1470000 J) / (120 s)

 

1 min = 60 seconds  --> 2 min = 120 seconds

 

12250 watts --> 1.225 x 10⁴ watts

 

How many sig-figs (significant figures)? scientific notation?