1. it takes a 25 n force to push a 250 n box across the floor.

a. how much work is done against friction when the box is moved 2 m across the floor?

b. how much work is done against gravity when the box is lifted 2 m above the floor?

A:- 50 J

B:- 500 J

Explanation:

a) Given that a 25 N force is applied to move the box. Also the floor is having friction surface.

So in order to move the box, the floor should have friction of atleast 25 N.

∴ friction = 25 N

Work done = force * displacement of box

Given, the box is moved 2 m across the floor

So, Work done = friction * 2 m

                         = 25 * 2

                         = 50 J

b) Given, the box is having weight of 250 N weight

Gravitational force is acting on the box which is equal to (mass * gravity)

∴ Force = 250 N

The box is lifted 2 m above the floor.

So, displacement = 2 m

Work done = force * displacement of box

Work done = 250 * 2

                   = 500 J

less than one you can't create energy

probably not the "magnets"in the magnet, so to speak, are thought to be electrons orbiting in shells. vurrent loops two sides to the loop