11. Block A and block B move toward each other on a level frictionless track. Block A has mass m and velocity +v. Block B has mass 2m and velocity -v. The blocks collide, and during the collision the
magnitude of the net force exerted on block A is F. What is the magnitude of the net force exerted
on block B, and why does it have that value?
a) 2F, because the mass of block B is twice that of block A and the blocks have
the same acceleration during the collision.
b) F/2, because the mass of block B is twice that of block A and the blocks have
the same acceleration during the collision.
c) F, because the blocks have the same speed immediately before the collision.
d) F, because the net force is equal to the mutual contact force between the
blocks.

The correct option is;

d) F, because the net force is equal to the mutual contact force between the blocks

Explanation:

The given information are

The mass of block A = m

The velocity of block A = +v

The mass of block B = 2·m

The velocity of block B = -v

Given that the two blocks collide, we have;

Initial total momentum = m × v + 2·m×(-v) = m·(v - 2·v) = -m·v

Final total momentum = m × v₁ + 2·m×v₂ = m·(v₁ + 2·v₂)

From the law of conservation of linear momentum, we have;

m·(v₁ + 2·v₂) = -m·v

v₁ + 2·v₂ = -v

Therefore, the resultant velocity of the two blocks is -v, and the direction of the block A is reversed and the resultant inertia is equivalent to the inertia of block A

Therefore;

The force exerted on block B = The force exerted on block A = The rate of change of momentum experienced by the two blocks = The mutual contact force experienced between the blocks.

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min