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.

Power = F*d/t = mg*d/t

=(60*10)*1.2/1.5 = 480 J/s = 480 Watts.

To determine the power expended by the weightlifter, we can use the formula:

Power = Work / Time

To calculate the work done by the weightlifter, we need to find the force exerted and the distance covered.

1. Calculate the force exerted:
Newton's second law states that the force (F) required to accelerate an object is given by the formula:

F = m * a

Where m is the mass of the object and a is the acceleration. In this case, the weightlifter is lifting the barbell vertically against gravity, so the acceleration is equal to the acceleration due to gravity (9.8 m/s^2).

F = 60 kg * 9.8 m/s^2
F = 588 N

2. Calculate the work done:
The work done (W) is given by the formula:

W = F * d

Where F is the force exerted and d is the distance covered. In this case, the weightlifter is lifting the barbell vertically, so the distance covered is equal to the vertical distance lifted (1.2 m).

W = 588 N * 1.2 m
W = 705.6 J (Joules)

3. Calculate the power:
Now that we have the work done, we can calculate the power by dividing the work by the time interval:

Power = 705.6 J / 1.5 s
Power = 470.4 W (Watts)

Therefore, the weightlifter expends 470.4 W of power when lifting the 60-kg barbell a vertical distance of 1.2 m in a time interval of 1.5 s.