Work and Energy...

Does the Law of Conservation of energy apply to machines?

Identify which of the following option best describe work.

A man with a box on his head is climbing up a ladder. What work is said to be done by the man on the box?

A $$3.0\ N$$ force applied on a $$0.40\ kg$$ mass makes the mass move at a constant speed of $$3.0\ {m}{s^{-1}}$$, held back by friction. In the span of it moving through $$4.0\ m$$, the net work done on the mass is:

SI unit of energy is  _________ .

Find the work done by a force of $$5 N$$ in displacing a book through $$20 cm$$ along the direction of the force.

When a stone tied to a string is whirled in a circle, what kind of work is said to be done on it by the string?

How much work is done in ergs in pulling a box $$2\ m$$ across a tabletop with a force of $$20\ N$$ in the horizontal direction?

1 horse power is equal to ______ watt :

Kinetic energy is present in the following: