Question

Two balls are set to collide on a single track. Ball1 has a mass of 2.90-kg and a velocity of 3.27-m/s Ball2 has a mass of 2.67-kg and a velocity of 1.27-m/s (NOT HEAD ON) After their elastic collision Ball1 is moving at 2.25-m/s in the opposite direction. How fast is Ball2 Moving?

Answer 1

Using momentum conservation before and after the collision

Pi = Pf

m1u1 + m2u2 = m1v1 + m2v2

m1 = mass of ball 1 = 2.90 kg

m2 = mass of ball 2 = 2.67 kg

u1 = initial speed of ball 1 = 3.27 m/sec

u2 = initial speed of ball 2 = 1.27 m/sec

v1 = final speed of ball 1 = -2.25 m/sec

v2 = final speed of ball 2 = ?

v2 = (m1u1 + m2u2 - m1v1)/m2

v2 = (2.90*3.27 + 2.67*1.27 - 2.90*(-2.25))/2.67

v2 = +7.26 m/sec (+ve sign means in the initial direction of ball 2)

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