Answer:

Explanation:
Given that,
Initial speed of the cart, u = 0
Let F force is applied to the cart for time
after which the car has speed v. The force on an object is given by :
F = ma
m is the mass of the cart
We need to find the speed of second cart, if the same force is applied for the same time to a second cart with twice the mass. Force becomes,



So, the speed of second cart is half of the initial speed of first cart. So, the correct option is (b).
Explanation:
Centripetal Force is the force that keeps the object's rotation in a circular path and it's always directed towards the center of rotation. Mathematically, it is given as,

From this equation it can be concluded that the centripetal force is proportional to the product of mass and the square of velocity. It is inversely proportional to the object's distance from the center.
Now in the above mentioned case, when the cylinder begins spinning very rapidly and it's speed becomes double. Then by applying the above equation we conclude that " the force will be increased four times if the speed is doubled as it is proportional to square of speed."