A 50 kg child is riding on a carousel (merry-go-round) at a constant speed of 5 m/s. What is the magnitude of the change in the child's momentum ∣Δp⃗ ∣∣ in going all the way around (360∘)?In going halfway around (180∘)? It is very helpful to draw a diagram, and to do the vector subtraction graphically.

a)

b)

Explanation:

From the image attached below.

Suppose the child goes all the way around, i.e., 360, the child will execute a movement of 1 complete revolution and be at his starting point. At that point, the velocity vector is towards the y-direction.

Thus, the velocity of the child is:

the momentum will be:

the  change in momentum now is since that is the child's momentum initially.

∴

By subtracting the two vector graphically as being asked in the question, we have :

b) In going halfway around (180°), the child will be opposite with respect to the starting point. Hence, the velocity vector will be in the negative y-direction.

Thus, the velocity of the child is:

the momentum will be:

the  change in momentum now is since that is the child's momentum initially.

∴

By subtracting the two vector graphically as being asked in the question, we have :

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.