Question

A model rocket rises with constant acceleration to a height of 3.1 m, at which point its speed is 28.0 m/s.

a. How much time does it take for the rocket to reach this height?
b. What was the magnitude of the rocket's acceleration?
c. Find the height of the rocket 0.10 s after launch.
d. Find the speed of the rocket 0.10 s after launch.

Answer 1

here,

intial height , h0 = 3.1 m

final speed , v = 28 m/s

a)

let the accelration be a

v^2 - u^2 =2 * a * s

28^2 - 0 = 2 * a * 3.1

solving for a

a = 126.5 m/s^2

let the time taken be t

v = u + a * t

28 = 0 + 126.5 * t

t = 0.22 s

the time taken to achive this speed is 0.22 s

b)

the magnitude of accelration is 126.5 m/s^2

c)

t1 = 0.1 s

the height of the rocket 0.10 s after launch , h = 0 + 0.5 * a * t1^2

h = 0 + 0.5 * 126.5 * 0.1^2 m

h = 0.63 m

d)

the speed of the rocket 0.10 s after launch , v = u + a * t1

v = 0 + 126.5 * 0.1 m/s

v = 12.65 m/s