In raising a 3000-N piano with a pulley system, it is noted that for every 2 m of rope pulled down, the piano rises 0.2 m. Ideally, what force is needed to lift the piano?

To solve this problem we will apply the principle of conservation of energy for which we have that the potential energy on a body, is equivalent to the work done on it at the given point. Therefore we will have the following equality

At the same time we know that work is equivalent to the Force applied over a given distance, so,

The potential energy is equivalent to the product between mass, gravity and height. Recall that the product of mass and gravity is equivalent to weight (The same given in the statement)

Equating,

Then,

Replacing,

Therefore the force needed to lift the piano is 600N

answer: he got 23

explanation:

c) up is the direction the magnetic force is acting on the charge.