Question

A 9.00 kg mass is moving to the right with a velocity of 14.0 m/s. A 12.0 kg mass is moving to the left with a velocity of 5.00 m/s. Assuming that these two balls have a head on collision and stick together, what will be the final velocity of the combination

Answer 1

Answer:

3.143 m/s

Explanation:

We are given;

• Mass of object A as 9.00 kg
• Velocity of A to the right is 14.0 m/s
• Mass of object B as 12.0 kg
• Velocity of B as 5.0 m/s to the left

We are required to determine the velocity after collision.

• We know that momentum before collision is equal to momentum after collision.
• Momentum before collision = momentum of A + momentum of B

• Taking the direction to the right as positive and to the left as negative

Momentum of A = 9.00 kg × (+14.0 m/s )

                           = 126 kgm/s

Momentum of B = 12.0 kg × (-5.0 m/s)

                            = -60 kgm/s

Thus; Momentum before collision = 126 - 60

                                                         = 66 kgm/s

Momentum after collision = Total mass of the body × Common velocity

                                           = ( 9 kg + 12 kg ) × V

                                           = 21 V kgm/s

But;

Initial momentum = Final momentum

66 kgm/s = 21 V kgm/s

Therefore;

V = 66 ÷ 21

   = 3.143 m/s

   = 3.143 m/s

Therefore, the common velocity of the bodies after collision is 3.143 m/s