A toy rocket is launched vertically from ground level (y = 0 m),at time t = 0.0 s.The rocket engine provides constant upward acceleration during the burn phase.At the instant of engine burnout,the rocket has risen to 64 m and acquired a velocity of 60 m/s.The rocket continues to rise in unpowered flight,reaches maximum height,and falls back to the ground.The time interval,during which the rocket engine provides upward acceleration,is closest to:
A)2.1 s
B)2.3 s
C)1.9 s
D)1.7 s
E)1.5 s

Question

Quizplus · Accepted Answer

The correct answer is A because the acceleration can be calculated as a = v/t = 60 m/s / 2.1 s = 28.57 m/s^2. The time interval during which the rocket engine provides upward acceleration is closest to 2.1 s.

A Toy Rocket Is Launched Vertically from Ground Level (Y