The ball spins at 7.7 rev/s. In addition, the ball is through with a linear speed of 19 m/s at an angle of 55 degrees with respect to the ground. If the ball is caught at the same height at which it left the quarterback's hand, how many revolutions has the ball made in the air?

Question

Thanks for your help

Answer 1

While ignoring air friction...

The vertical speed of the ball is 19sin55.

hf=ho+viy*t- 1/2 g t^2
0=19sin55*t-4.9t^2
solve for time in air, t.

revolutions= 7.7*timeinair

Answer 2

am sorry but could you explain how you got 7.7 revolutions as your final answer ? I do 19sin of 55 I get =15.5639 and then Im lost , thanks again

Answer 3

The 15.5639 is the time in second while the 7.7 is the rev per second. So the final answer should be the time times revolutions per second.