Question

tennis ball projected at an angle attain a range R=78m if the velocity imported to the ball by rocket is 3oms-1 calculate angle take g = 10ms-1

Answer 1

When a ball is hit by a tennis, it performs projectile motion

Let u be the velocity with which ball is projected at an angle theta

As given in the Question,

Velocity of the ball,
               
                         u = 30 m/s

Range is also given
                   
                       R = 78 m

We know the formula of Range in projectile Motion as,

                      R = (u^2/g) (Sin2theta)
  
Putting the values we get,

                          78 = (30^2/9.8) (SIn2theta)
                          78 = (900/9.8) (Sin2theta)
                         Sin2 theta = (78 * 9.8) / 900
                          Sin2theta = 13*49 / 750
                          2 SIntheta Cos theta = 637 / 750

Answer 2

Answer:

30°

Explanation:

R=u^2sin2thetha/g

78=30^2sin2theta/10

78*10=30^2sin2theta

780=900sin2theta

780\900=sin2theta

0.8667=sin2theta

Inverse of 0.8667=60

60°=sin2theta

60°\2=sin2theta\2

Sin theta =30°