A foot ball is kicked of with an initial speed of 19.6 m/sec at a projection angle 45^(0). A receiver on the foal line 67.4m away in the direction of the kick starts running to meet the ball at that instant. What musthis speed be if he is to catch the ball before it hits the ground?

A foot ball is kicked of with an initial speed of 19.6 m/sec at a proj

1.	A foot ball is kicked of with an initial speed of 19.6 m/sec at a projection angle 45^(0). A receiver on the foal line 67.4m away in the direction of the kick starts running to meet the ball at that instant. What musthis speed be if he is to catch the ball before it hits the ground?
Answer» Solution :`R=(u^(2)SIN2THETA)/(g)=((19.6)^(2)xxsin90)/(9.8)` or R=398.2metre. Man must run 67.4m - 39.2m = 28.2m in the TIME taken by the ball to come to ground. Time taken by the ball. `t=(2usintheta)/(g)=(2xx19.6xxsin45^(0))/(9.8)=(4)?SQRT(2)` `t=2sqrt(2) = 2xx1.41 = 2.82` sec. velocity of man =` (28.2m)/(2.82m)=` 10m/sec.