A 120 g ball moving to the right at 4.5 m/s catches up and collides with a 410 g

ID: 1363480 • Letter: A

Question

A 120 g ball moving to the right at 4.5 m/s catches up and collides with a 410 g ball that is moving to the right at 1.2 m/s .

1- If the collision is perfectly elastic, what is the speed of the 120 g ball after the collision?

2- If the collision is perfectly elastic, what is the direction of motion of the 120 g ball after the collision?

3- If the collision is perfectly elastic, what is the speed of the 410 g ball after the collision?

4- If the collision is perfectly elastic, what is the direction of motion of the 410 g ball after the collision?

here,

mass of ball 1 , m1 = 0.12 kg

mass of ball 2 , m2 = 0.41 kg

u1 = 4.5 m/s

u2 = 1.2 m/s

let the final speed of the balls be v1 and v2

using conservation of momentum

m1*u1 + m2*u2 = m1*v1 + m2 * v2

0.12 * 4.5 + 0.41*1.2 = 1.12 *v1 + 0.41*v2 ....(1)

using consqervation of kinetic energy

using conservation of momentum

0.5 * m1*u1^2 + 0.5 *m2*u2^2 = 0.5 * m1*v1^2 + 0.5 * m2 * v2^2

0.12 * 4.5^2 + 0.41*1.2^2 = 1.12 *v1^2 + 0.41*v2^2 ....(2)

from equation (1) and (2)

v1 = - 0.61 m/s

v2 = 2.69 m/s

If the collision is perfectly elastic, what is the speed of the 120 g ball after the collision is 0.61 m/s

If the collision is perfectly elastic, what is the direction of motion of the 120 g ball after the collision towards left

If the collision is perfectly elastic, what is the speed of the 410 g ball after the collision 2.69 m/s

If the collision is perfectly elastic, what is the direction of motion of the 410 g ball after the collisio towards right

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