Question

A 3.0 kg mass moving to the right at 1.4 m/s collides in a perfectly inelastic collision with a 2.0 kg mass initially at rest. what will the velocity of the combined mass be after the collision? show your work.

Answer 1

Solution Formula total velocity, V =mass 1 Ă— velocity 1 + mass 2 Ă— velocity 2 â• mass 1 + mass 2 Given mass 1 = 3.0 kg, velocity 1 = 1.4 m/s, mass 2 = 2.0 kg, velocity 2 = 0 m/s V = 3.0 Ă— 1.4 + 2.0 Ă— 0 â• 3.0 + 2.0 V = 0.84 m/s

Answer 2

Answer:

0.84 m/s

Explanation:

we can solve the problem by using the law of conservation of momentum: the initial momentum must be equal to the final momentum, so we can write

$p_i = p_f$

$m_1 u_1 + m_2 u_2 = (m_1 +m_2 )v$

where

$m_1 = 3.0 kg$ is the first mass

$u_1=1.4 m/s$ is the initial velocity of the first mass

$m_2 = 2.0 kg$ is the second mass

$u_2 = 0$ is the initial velocity of the second mass

$v$ is the final velocity of the two combined masses after the collision

Re-arranging the equation and substituting the numbers, we find

$v=\frac{m_1 u_1 +m_2 u_2}{m_1+m_2}=\frac{(3.0)(1.4)-0}{3+2}=0.84 m/s$