With the help of a movable block, water with a volume of 10 liters is raised to a height of 4 m

With the help of a movable block, water with a volume of 10 liters is raised to a height of 4 meters. What force is applied to the rope and what work is done?

These tasks: the water was raised using a movable block; V (volume of raised water) = 10 l (in SI V = 0.01 m3); h (water rise) = 4 m.

Reference values: g (acceleration due to gravity) ≈ 10 m / s2; ρw (density of the raised water) = 1000 kg / m3.

1) The force applied to the rope (the gain in strength is 2 times): F = P / 2 = m * g / 2 = ρw * V * g / 2 = 1000 * 0.01 * 10/2 = 50 N.

2) Perfect work (there is no gain in work): A = ΔEp = m * g * h = ρw * V * g * h = 1000 * 0.01 * 10 * 4 = 400 J.