Question #3844

A 0.50 kg ball traveling at 6.0 m/s collides head-on with a 1.00-kg ball moving in the
opposite direction at a velocity of –12.0 m/s. <br>The 0.50 kg ball moves away at –14 m/s after
the collision. Find the velocity of the second ball.

Expert's answer

Let m_{1} be the mass of the first ball (m_{1} = 0.5 kg), m_{2} - the mass of the second ball (m_{2} = 1 kg).

U_{1}, V_{1} - speeds of the first ball before and after the collision, U_{2}, V_{2} - speeds of the second ball before and after the collision.

According to the law of conservation of linear momentum (let the initial direction of the first ball be positive):

m_{1}U_{1 }- m_{2}U_{2}=-m_{1}V_{1 }+ m_{2}V_{2}

V_{2 }= (U_{1 }+ V_{1})*m_{1}/m_{2 }- U_{2}

V_{2 }= (6 + 14)*0.5/1 - 12 = -2 m/s.

So, the second ball continued moving at the same direction at 2 m/s.

U

According to the law of conservation of linear momentum (let the initial direction of the first ball be positive):

m

V

V

So, the second ball continued moving at the same direction at 2 m/s.

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