Three balls of clay with m1=40 g, m2=30 g and m3=20 g are moving with velocities v1=4.0 m/s
at 315 deg, v2=3.0m/s at 180 deg and v3=2m/s at 90deg respectively (all angles are given relative to
the +x axis). The masses collide and create a single blob of clay.

A)Determine the magnitude and direction of the blob after the collision.
B)Determine the velocity of the center of mass before the collision.

Question

Three balls of clay with m1=40 g, m2=30 g and m3=20 g are moving with velocities v1=4.0 m/s
at 315 deg, v2=3.0m/s at 180 deg and v3=2m/s at 90deg respectively (all angles are given relative to
the +x axis). The masses collide and create a single blob of clay.

A)Determine the magnitude and direction of the blob after the collision.
B)Determine the velocity of the center of mass before the collision.

anonymous · Answer

The momentum will be conserved. 

First, calculate the momentum of the three object independently. Find the component in the x and y direction. 

Second, find the velocity after the collision.  $$m_1 v_1 + m_2 v_2 + m_3 v_3 = (m_1 + m_2 + m_3) v'$$Use this equation for the velocity in the x and y directions. 

The center of mass will move in the same was as the blob. That is, there velocities will be the same.