Question 32: A football player is moving southward and suddenly turns eastward with the same speed to avoid an opponent. The force that acts on the player while turning is :
(1) along north-east
(2) along south-west
(3) along eastward
(4) along northward
Answer: Option (1)
Explanation:
Force acting on a body is related to the rate of change of velocity, given by
\vec{F}=m\vec{a}. Hence, the direction of force is the same as the direction of change in velocity.
Initially, the player is moving southward. After turning, the player moves eastward with the same speed.
Thus, there is a change only in the direction of velocity, not in its magnitude.
The initial velocity vector is directed southward and the final velocity vector is directed eastward.
The change in velocity vector is obtained by subtracting the initial velocity from the final velocity.
This change in velocity has a component toward the north (opposite to south) and a component toward the east. Therefore, the direction of change in velocity is along north-east.
Since force acts in the direction of change in velocity, the force acting on the player while turning is along north-east.
Hence, the correct answer is Option (1).