Question

A hockey player is moving north ward and suddenly turns westward with the same speed to avoid an opponent. The force that acts on the player is.

• A. Frictional force along westward.
• B. Muscle force along southward.
• C. Frictional force along south west.
• D. Muscle force along south – west.

Answer 1

Answer: (C)

Frictional force along south west.

Answer 2

In figure $\overset{\rightarrow}{OA} = \overset{\rightarrow}{p_{1}} =$initial momentum of player northward

$\overset{\rightarrow}{OB} = \overset{\rightarrow}{p_{2}} =$final momentum of player westward

According to triangle law of vectors,

$\overset{\rightarrow}{OA} + \overset{\rightarrow}{AB} = \overset{\rightarrow}{OB}$

$\overset{\rightarrow}{AB} = \overset{\rightarrow}{OB} - \overset{\rightarrow}{OA} = \overset{\rightarrow}{p_{2}} - \overset{\rightarrow}{p_{1}} =$change in momentum

The change in momentum of player is along south west As motion is due to frictional force of reaction of the ground therefore force that acts on the player is frictional force along south west