A particle is projected with speed 20 m s- 1 at an angle 30° with horizontal. After how much time the angle between velocity and acceleration will be 90°

Question

A particle is projected with speed 20 m s- 1 at an angle 30° with horizontal. After how much time the angle between velocity and acceleration will be 90°  (A) 1 s (B) 2 s (C) 1.5 s (D) never

Tardigrade Admin · Accepted Answer

Acceleration g is vertically downward To make velocity perpendicular to acceleration, velocity must be horizontal. This is possible at maximum height. For this vy=0 uy=usin θ uy=20sin30° =10 m s- 2 g=-10 ms- 2 We know that vy=uy+gt By putting all value, we get t=1 texts

Q. A particle is projected with speed $20 m s^{- 1}$ at an angle $3 0^{\circ}$ with horizontal. After how much time the angle between velocity and acceleration will be $9 0^{\circ}$

$1 s$

$2 s$

$1.5 s$

never

Q. A particle is projected with speed 20ms−1 at an angle 30∘ with horizontal. After how much time the angle between velocity and acceleration will be 90∘

1s

2s

1.5s

never

Acceleration g is vertically downward To make velocity perpendicular to acceleration, velocity must be horizontal. This is possible at maximum height. For this vy​=0 uy​=usinθ uy​=20sin30∘=10ms−2 g=−10ms−2 We know that vy​=uy​+gt By putting all value, we get t=1s

Q. A particle is projected with speed $20 m s^{- 1}$ at an angle $3 0^{\circ}$ with horizontal. After how much time the angle between velocity and acceleration will be $9 0^{\circ}$

$1 s$

$2 s$

$1.5 s$