With the help of a winch, a body weighing 40 kg is lifted to a height of 30 meters. What kind of work does gravity do?

To find the desired work of gravity when lifting a taken body with a winch, we will use the formula: A = F * S * cosα = m * g * h * cosα.

The values of the variables: m is the mass of the lifted body (m = 40 kg); g – acceleration due to gravity (g ≈ 10 m / s2); h – lifting height (h = 30 m); α is the angle between the vectors of displacement of the lifted body and the force of gravity (α = 180º).

Calculation: A = m * g * h * cosα = 40 * 10 * 30 * cos 180º = -12 * 10 ^ 3 J = -12 kJ.

Answer: The work of gravity is -12 kJ.