Question

a body of mass 5kg collides with another body of mass 2.5kg at rest after collision both the bodies stick together and move with ke 5 find ke of first body before collision​

Answer 1

Answer:5.625

Explanation:

Answer 2

Answer: 12.656 J

Explanation:

First of all, final K.E. = 5

(5+2.5)×1/2× (v^2) = 5

V final (same for both bodies) = 1.15m/s

Here, as any external force is absent, momentum will remain conserved. So,

Pi = pf

》 m1u1 + m2u2 = mf1vf1+ mf2vf2

》5×u1 + 0 = (2.5+5)×1.5

On solving this equation ,

U1 = 2.25m/s

This implies that:

Initial K.E. of 1st body : 1/2 mv^2

1/2 × 5 × (2.25)^2

=12.656 J

Hope it helps :)