Ncert Exercises & Solutions

A hockey player is moving northward and suddenly turns westward at the same speed to avoid an opponent. The force that acts on the player is:

1.	frictional force along westward
2.	muscle force along southward
3.	frictional force along south-West
4.	muscle force a south-West

Step 1: Find the direction of change in momentum.

Consider the adjacent diagram

Let,

\begin{array}{l} OA = p_{1} \\ = Initial momentum of player northward \\ AB = p_{2} = Final momentum of player towards west. \\ Clearly, OB = OA + AB \end{array}

in momentum

= p_{2} - p_{1}

= AB - OA = AB + (-OA)

= Clearty ræultant AR will along souttm-west.