Question

The work done in pushing a block of mass 10kg from top to bottom of a frictionless incline plane 5mlong and 3m high is?

Answer 1

Work done = Force × distance.

The force acting on the block is the normal force.

Force = Mg Cos Ф

Cos = adjacent / hypotenuse

By pythagoras theorem.

Adjacent = √(5² - 3²) = √16 = 4

Cos Ф = 4/5 = 0.8

Take g = 10

F = 10 × 10 × 0.8 = 80 N

Here the distance covered is the height.

Work = 80 × 3 = 240 Joules

240 joules