Momentum in 2D

Which is the correct statement for explosions and collisions?

• As long as there are external forces acting the sum of the total momentum's before should equal the sum of the total momentum's after! However, the momentum's have to be calculated as vectors with direction.

• As long as there are no external forces acting the sum of the total momentum's before should equal the sum of the total momentum's after! However, the momentum's don't have to be calculated as vectors with direction.

• As long as there are no external forces acting the sum of the total momentum's before should not equal the sum of the total momentum's after! However, the momentum's have to be calculated as vectors without direction.

• As long as there are no external forces acting the sum of the total momentum's before should equal the sum of the total momentum's after! However, the momentum's have to be calculated as vectors with direction.

The 0.5 kg ball travelling at 3ms^-1 hits the stationary 0.8 kg ball. Afterwards the 0.5 kg ball is travelling at 0.5 ms^-1. Calculate the 0.8 kg balls velocity.

• 2 ms^-1

• 1.85 ms^-1

• 0.25 ms^-1

• 0.1 ms^-1

The 0.5 kg ball travelling at 10ms^-1 hits the stationary 0.8 kg ball. Afterwards the 0.5 kg ball is travelling at 2.5 ms^-1. Calculate the systems centre of masses velocity.

• 3.85 ms^-1

• 10 ms^-1

• 2.5 ms^-1

• 6.05 ms^-1

The 15g marble moves at 1.1 ms^-1 towards the stationary 25g marble. Afterwards both marbles move in different directions (15 g at 0.95ms^-1) as shown. Calculate the velocity of the 25g marble.

• 1.5 ms^-1

• 0.06 ms^-1

• 0.33 ms^-1

• 0.4125 ms^-1

The 15g marble moves at 1.1 ms^-1 towards the stationary 25g marble. Afterwards both marbles move in different directions as shown. Calculate the velocity of the COM of the system.

• 1.5 ms^-1

• 0.06 ms^-1

• 0.033 ms^-1

• 0.41 ms^-1

Calculate the centre of mass of the system and Ivan (90kg) when he and Natalia (75 kg) are 30 m apart.

• 13.64 m

• 15 m

• 16.36 m

• 10 m

Calculate the combined speed of the astronauts after they collide.

• 66.16 ms^-1

• 50.16 ms^-1

• 56.16 ms^-1

• 6.16 ms^-1

Calculate the velocity of the centre of mass of the system!

• 66.16 ms^-1

• 50.16 ms^-1

• 56.16 ms^-1

• 6.16 ms^-1

Debris 35kg, speed 65ms^-1 and a satellite - 200kg, speed 100 ms^-1 are 48000 m apart. Calculate COM of the system from the debris.

• 36226.42 m

• 11773.58 m

• 24000 m

• 35629.43 m

Debris 35 kg, speed 65 ms^-1 and a satellite - 200 kg, speed 100 ms^-1 are 48000 m apart. Calculate the speed and direction relative to the initial satellite direction/speed of the debris/satellite mass movement after collision.

• 50.98 ms^-1 90 degrees to the horizontal

• 50.98 ms^-1 90 degrees to the vertical

• 85.66 ms^-1 6.49 degrees to the vertical

• 85.66 ms^-1 89.35 degrees to the horizontal