Chapter 6- Work, Energy And Power

Question 1

Define kinetic energy

Answer 1

Kinetic energy is the energy a body possesses due to its motion.

Formula: kinetic energy= 1/2mv^2

Question 2

Define gravitational potential energy

Answer 2

Gravitational potential energy is the energy a body possesses because of its position relative to the ground

GPE= mgh

Question 3

State the principle of conservation of energy

Answer 3

The principle of conservation of energy states that energy cannot be created or destroyed but only, changes from one form to another

Question 4

Define Work

Answer 4

Work done by an object is the amount of energy that has been converted from one form to another or transferred from one body to another. It is a scalar quantity. SI unit: Joule

Work done= Force x Distance moved in direction of force

Question 5

Define power

Answer 5

Power is defined as the rate of doing work. Since work involves energy, power is also the rate at which energy changes form one form to another

Power= workdone/time

Question 6

Define efficiency

Answer 6

Efficiency of a system is defined as the ratio of useful energy output to the total energy input of the system

Efficiency= useful energy output/total energy input x 100%

Question 7

Define energy

Answer 7

Energy is defined as the capacity to do work. It is a scalar quantity. Energy can be converted from one form to another