Show that 480 W of power is expended by a weightlifter when lifting a 60-kg barbell a vertical distance of 1.2 m in a time interval of 1.5 s.

Answer 1

Work done
=mgh
= 60 kg * 9.8 m/s² * 1.2 m
= 705.6 j
Power
= work done / time
= 705.6 j / 1.5 s.
= 470 watts (approximately)

The difference may be due to the assumed value of g in the question.