Question

A ship moving in sea can't be stopped quickly by applying brakes due to:
A.Low friction
B.Excessive friction
C.High speed
D.None of the above

Answer 1

Hint: A ship moving in sea has a friction between the submerged part of the ship and water. Friction depends on the speed of the object which in this case is a ship and the viscosity of liquid. And it also depends on the part of the ship submerged in the fluid.

Complete answer:
The basic working principle of brake is, it creates a friction between the wheel and a stationary body with which the wheel is in contact with. This friction is created to stop the motion of the wheel.
When a ship moves in water, a viscous drag is generated between the submerged surface of the ship and the water particles which are in contact with the submerged surface of the ship. It is due to the viscosity of water. This viscous drag is directly proportional to the amount of surface area of the ship which is wet.
Coefficient of force is less between the wheel of the ship and water. Thus, the friction is also less. Hence, due to less friction, the ship moving in sea cannot be speed quickly after applying brakes.

Hence, the correct answer is option A i.e low friction.

Note:
Friction exerted by water is less as compared to liquids. Fishes in the water have a streamlined body to resist fluid friction. Swimmers also experience fluid friction. Due to this fluid friction, it becomes slippery while walking sidewalks on the road or floor when it gets wet. As the speed increases, friction on the body also increases.