Mr C.P. Nawani kicked off a football with an initial speed $$19.6$$ $$m/s$$ at a projection angle $$45$$º. A receiver on the goal line $$67.4$$ m away in the direction of the kick starts running to meet the ball at that instant. What must be his speed so that he could catch the ball before hitting the ground? (g=$$ $$9.8$$ $$m/s2)

Question

Infinity Learn · Accepted Answer

range is $$R=u2sin2$$θ$$g=(19.6)2sin90$$∘$$9.8=39.2m$$; 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. time of flight is $$t=2usin$$θ$$g=2$$×$$19.6sin45$$∘$$9.8$$ $$time=42=2.82sec$$ Velocity of man $$=displacementtime=28.2m2.82sec=10m/s$$

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