Problem 8-82 Impulse-momentum

A football of mass \(0.41\; kg\) is kicked from rest and given a velocity of \(24 \;m/s\) at \(29^\circ\) above the horizontal. The ball is in contact with the kicker's foot for \(8.2\; m/s.\) Determine:

(a) the horizontal and vertical components of the ball's momentum
(b) the horizontal and vertical components of the average force exerted by the foot on the ball (using momentum methods)
(c) the magnitude and direction of the force in (b).

[Ans. (a) \(8.6 \;kg \;m/s; \;4.8 \;kg \;m/s\)   (b) \(1.0\times 10^3 \;N; 5.8\times 10^2 \;N\)   (c) \(1.2\times 10^3\; N\; \text{at} \; 29^\circ \; \text{above horizontal}\) ]


The first thing required is a drawing of the situation and the selection of a suitable coordinate system. Which of the following would you choose as the best?

Four possible coordinate systems.

(A)

(B)

(C)

(D)