8-82 A football
of mass 0.41 kg is kicked from rest and given a velocity of 24 m/s at
29°
above the horizontal. The ball is in contact with the kicker's foot for
8.2 ms. 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) 1.0X103 N; 5.8X102 N (c)
1.2X103
N at 29°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?
