Subject Experts Solutions for Chapter: Energy, Exercise 2: Check your progress

Mechanical energy is of two types - potential energy and kinetic energy.

Kinetic energy of an object is the energy stored in it.

Kinetic energy of an object depends on its mass and velocity.

The energy stored in an object due to its raised position is known as elastic potential energy.

A ball thrown from a balcony possesses kinetic energy.

A child lifts a book of mass $1 \mathrm{kg}$ from the table to a cupboard at the height of $2 \mathrm{m}$ from the floor. What is the potential energy of the book with respect to the floor?$\left(\mathrm{g}=9.8 \mathrm{m} {\mathrm{s}}^{-2}\right)$

What is the speed of a runner of mass $50 \mathrm{kg}$ whose kinetic energy while running is $2500 \mathrm{J}$?

A child climbs a wall of height $4 \mathrm{m}$. He now possesses a potential energy of $1600 \mathrm{J}$. What is the mass of the child? $\left(\mathrm{g}=9.8 \mathrm{m} {\mathrm{s}}^{-2}\right)$