5)
a) Define the term 'energy' of a body. What is the SI unit of energy.
b) What are the various forms of energy?
c) Two bodies having eqaul masses are mvoing with uniform
speeds of vand 2v respectively. Find the ration of their kinetic
energies.
6)a)What is you understand by the kinetic energy of a body?
b)A body is thrown vertically upwords. Its velocity goes on
decreasing. What happens to its kinetic energy as its velocity
becomes zero?
c)A horse and a dog are running with the same speed. If the
weightof the horse is ten times that of the dog, what is the
ratio of their kinetic energies?
(The one who gives all ans correctly will be marked as brainliest)
Answers
5)
a) Energy is defined as the ability to do work and joule is the SI unit of energy.
b)Forms of energy:
Kinetic energy, potential energy, nuclear energy, electrical energy, chemical energy, sound energy, light energy, and heat energy.
c)Let the mass of both the bodies be m
Velocity of body 1,v1=v
Velocity of body 2,v2=2v
KE 1 =1/2mv^2
=1/2m(v 1 )^ 2
KE 2=1/2mv^2
=1/2m(v 2 ) ^2
Ratio=KE 1 :KE 2 =1/4
6)
a) Kinetic energy of a body is the energy due to motion.
b) The kinetic energy of the body will be equal to zero as kinetic energy is directly proportional to the square of the velocity. Therefore , when a body is thrown vertically upwards , the kinetic energy becomes zero.
c) Speed of horse = speed of dog = v
Weight of dog = m
Weight of horse =10m
KE1 is the for dog =1/2mv^2
KE2 is for horse =1/2mv^2 =1/2(10m)v ^2
Ratio=KE1:KE2=10/1
Need to Understand!