Question

A football is kicked 20m/s at a projection angle of 45°.

Answer 1

Answer:

Range of projectile = (u² sin2x)/g

= (20×20×1)/10

= 40m

Time taken by ball to fall down = (u sinx)/g

= (20×1/√2)/10

= √2sec

Now , Distance that goalkeeper should travel

= 40-25

= 15m

Time should be taken by him = √2sec

so his speed = distance / time

= 15/√2m/s.