Answer:
3/5 v
Explanation:
The computation of speed will the alpha particle have after the collision is shown below:-
In a perfectly elastic the kinetic energy and collision the momentum are considered.
The velocity of the particles defines the below equation:

As we know that


Here, we consider A is the alpha particle and B is the proton and now by the above values we can solve the equation which is below:-



Therefore the correct answer is 
Answer:
The free body diagram is attached.
Explanation:
A force of 31[N] to the east, the second force goes to the south and it is equal to 28[N], the third force goes to the west and it is equal to 39 [N].
We can consider the crate as a particle. And all the forces are acting over the particle.
Answer:
The balloon will collapse
Explanation:
When air is removed from the bell jar, the balloon will collapse if the internal pressure from the balloon does not balance the atmospheric pressure from the surroundings.