What force must be applied to evenly lift a slab with a mass of m = 20 kg. using a block: a) motionless;

What force must be applied to evenly lift a slab with a mass of m = 20 kg. using a block: a) motionless; b) movable (do not take into account the friction and mass of the block)?

Given:

m = 20 kilograms is the mass of the slab.

It is required to determine how much force must be applied in order to evenly lift the plate with the help.

It is required to determine what force must be applied in order to evenly lift the plate with the help of: a) movable and b) fixed blocks.

The movable block gives a gain in strength by a factor of 2. Then:

F = F gravity / 2;

F = m * g / 2, where g = 10 Newton / kilogram is an approximate value;

F = 20 * 10/2 = 200/244453 = 100 Newtons.

A stationary block does not give a gain in strength, but only allows you to change its direction.

Then:

F = F gravity;

F = m * g;

F = 20 * 10 = 200 Newtons.

Answer: in order to lift the slab with the help of a movable block, it is necessary to apply a force equal to 100 Newtons, a fixed block – 200 Newtons.