A 0.86kg grenade is tossed on the ground with a velocity of 6 m/s West. If the grenade explodes into 2 pieces, one that has a mass of 32kg and travels East at 10 m/s.
(A) What is the mass of the second piece
(B) What is the velocity of the second piece?

(A) 0.54 kg

(B) 15.5 m/s west

Explanation:

Mass is conserved.

M = m₁ + m₂

0.86 kg = 0.32 kg + m₂

m₂ = 0.54 kg

Momentum is conserved (take east to be positive).

Mv = m₁v₁ + m₂v₂

(0.86 kg)(-6 m/s) = (0.32 kg)(10 m/s) + (0.54 kg) v₂

v₂ = -15.5 m/s

answer///terminator or twilight zone;

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.