Consider a long train moving at speed v. Now consider a passenger throwing a ball inside this train, towards the back of the train, with same velocity v (but in the opposite direction of the train movement).
- A passenger inside the train will see the ball moving with speed v
- For an observer outside the train, however, the ball will appear as still. In fact, for him the ball will have a speed v (given by the movement of the train) -v (velocity of the ball but moving in the opposite direction), so the net velocity will be v+(-v)=0.
Answer:

Explanation:
The final velocity is given by the following kinematic equation:

Here,
is the initial velocity, a is the body's acceleration and t is the motion time. We have to convert the time to seconds:

Now, we calculate the final velocity:

Hello!
The answer that makes most sense to me is option A.
~ Hope I helped! ~
Explanation:
the formula for momentum is denoted by p=mv where p is momentum, m is mass and v is velocity. thus, the velocity before impact would be 0.060 x 30 = 1.8 kg/ms
the second one would just be 0.060 x 20 0.72kg/ms
I'm not 100 percent sure this is correct but yeah