The weightlifter lifted a barbell weighing 125 kg to a height of 70 cm in 0.3 s.

The weightlifter lifted a barbell weighing 125 kg to a height of 70 cm in 0.3 s. What average power did the athlete develop while doing this?

m = 125 kg.

g = 9.8 m / s ^ 2.

h = 70 cm = 0.7 m.

t = 0.3 s.

N -?

Power N is called the speed of performing mechanical work A. Power N is determined by the formula: N = A / t, where t is the time of performing the work.

Work A is equal to the change in the potential energy Ep of the rod: A = ΔEp.

The change in potential energy ΔЕп is found by the formula: ΔЕп = m * g * h, where m is the mass of the bar, g is the acceleration of gravity, h is the height of the bar.

The formula for determining the power will take the form: N = m * g * / t.

N = 125 kg * 9.8 m / s ^ 2 * 0.7 m / 0.3 s = 2858 W.

Answer: when lifting the bar, the athlete developed a power of N = 2858 W.