Question

A body of mass is 5kg moving with a velocity of 20m due south hits a stationary body of mass is 3kg if they move together after collision with a velocity due south what is d value of l

Answer 1

Well, I do not know what
"d value of l "
means but
final momentum south = initial momentum south
so
5 * 20 = (5+3) * new v south = momentum before and after
100 = 8 v
v = 100/8 m/s south

Answer 2

Given:
M1 = 5kg, V1 = - 20m/s.
M2 = 3kg, V2 = 0.
V3 = Velocity of M1 and M2 after colliding.

Momentum before = Momentum after.
M1*V1 + M2*V2 = M1*V3 + M2*V3.
5 *(- 20) + 3 * 0 = 5V3 + 3V3,
8V3 = -100,
V3 = -12.5 m/s = 12.5 m/s, South.

Answer 3

Thanks