Two toy-cars A and Bof masses 200 g and 500 g respectively are moving with the same speed. Which of the two has greater kinetic energy ?
CAR A CAR B
mas= 200g mass = 500 g
=`200/1000`=`1/5` kg =`500/1000`=0.5 kg
K.E.=`1/2` M`V^2` ∴ speed of both cars is same
K.E. =`1/2`× 0.2 ×`V^2` K.E. of B=`1/2` ×0.5× `V^2`
=0.1 `v^2` =0.25 `v^2`
0.25 `v^2` is greater than 0.1`v2`
∴ K.E. of car B is greater.
Since speed of both cars is same
∴ The speed of car having greater mass (i.e. of car B), the K.E. is greater
∴ Kinetic energy of car B having greater mass is greater.