Question

Calculate the velocity of a body of mass 4 kg possessing KE of 0.02J.

Answer 1

This problem is based on the relation between kinetic energy and velocity of an object. Kinetic energy of an object is proportional to mass and square of velocity of object. So here we use this relation to find the velocity of the body.

Complete step by step answer:
As we know that the kinetic energy of an object is proportional to mass of object and square of velocity of object. The relation can be represented as-
$K.E. = \dfrac{1}{2}m{v^2}$
Here, m= Mass of object
v= Velocity of object
The given values in question are
Mass of object (m)= 4kg
K.E. of object= 0.02J
So here we put these values in given formula to calculate the velocity of object-
$0.02 = \dfrac{1}{2} \times 4 \times {v^2}$
${v^2} = \dfrac{{0.02}}{2}$
${v^2} = 0.01$
$v = \sqrt {0.01}$
$v = 0.1m/s$
So the velocity of the object is 0.1m/s.
The kinetic energy of an object is due to its motion. If the object is at rest then its velocity will be zero, so the kinetic energy will also be zero.
The total energy of an object is given by the sum of its kinetic energy and potential energy. The potential energy is due to its position from ground level or reference level. The kinetic energy is due to its motion.
The law of conservation of energy states that energy can neither be created nor destroyed, only converted from one form of energy to another. This means that a system always has the same amount of energy.

Note: Kinetic energy is a type of energy which depends on mass of object and speed of object. If we change the mass or speed of an object then its kinetic energy will also change.