A ball with a mass of $2 kg$ is rolling at $1 m/s$ and elastically collides with a resting ball with a mass of $3 kg$ . What are the post-collision velocities of the balls?

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Answer 1 · 2016-04-25T12:30:34

$u_1=-1/5 m/s$
$u_2=4/5 m/s$

$"given data:"$
$m_1=2kg$
$v_1=1m/s$
$"Momentum before collision for the first ball:"$
$vec P_1=m_1*v_1=2*1=2 kg*m/s$

$m_2=3 kg$
$v_2=0$
$"momentum before collision for the second ball:"$
$vec P_2=3*0=0$

$"Total momentum before collision:"$
$vec P_b=vec P_1+vec P_2$
$vecP_b=2+0=2 kg*m/s$

$"Velocities for post collision :"$

$u_1:"Post collision velocity of the first ball"$

$u_1=(2*vec P_b)/(m_1+m_2)-v_1$

$u_1=(2*2)/(2+3)-1$

$u_1=4/5-1$

$u_1=-1/5 m/s$

$u_2:"Post collision velocity of the second ball"$

$u_2=(2*vec P_b)/(m_1+m_2)-v_2$

$u_2=(2*2)/(2+3)-0$

$u_2=4/5 m/s$

A ball with a mass of 2 kg2 kg is rolling at 1 m/s1 m/s and elastically collides with a resting ball with a mass of 3 kg3 kg. What are the post-collision velocities of the balls?