Question

A rocket is fired at a ground level target 600 m away with initial velocity 85 m/s. Find the two possible value of the launch angel. calculate the minimum time to hit the target......??

Answer 1

R=u^2SIN 2THETA /G
600 =85*85 SIN 2THETA 9.8

Answer 2

Explanation:

R= (85×85)sin2theta /g

600= (7225)sin2theta/9.8

600×9.8 = (7225) sin2theta

5880/7225 = sin2theta

0.81 = sin2theta

sin inverse (0.81) = 2theta

54 = 2theta

54/2 = theta

27° = theta

now this is the minimum value of angle theta to find the maximum value

theta max = 90° - 27°

theta max = 63°

now to find the minimum time we have to take the minimum value of theta

T minimum = 2(85) sin(27)/9.8

T minimum= (170)(0.45)/9.8

T minimum = 7.9seconds

so the minimum time to hit the target is 7.9seconds