Question

the velocity of a particular mass is reduced to ¼ of its initial value. find the change in kinetic energy ​

Answer 1

Answer:

Let the mass be m kg.

Initial Velocity (u) = v m/s

Final Velocity (v) = v - (1/4 of v)

= v - v/4

= ( 4v - v )/4

= 3v/4

Kinetic Energy (Initial) = 1/2*m*v²

= mv²/2 J

Kinetic Energy (Final) = 1/2*m*v²

= 1/2*m*(3v/4)²

= 1/2*m*9v²/16

= 9mv²/32 J

Change in Kinetic Energy = mv²/2 - 9mv²/32

= ( 16mv² -  9mv² ) / 32

= 7mv²/32 J

I hope this helps.