Question

A model rocket accelerates upward from the ground with a constant acceleration, reaching a height of 50 m in 8 s.What is the speed (in m/s) at a height of 50 m?A: 1.07×101 B: 1.25×101 C: 1.46×101 D: 1.71×101 E: 2.00×101

Answer 1

The value is
`v =  12.5 \  m/s`

Step-by-step explanation:

From the question we are told that

The height is
`h  =  50 \  m`

The time taken is
`t =  8 \ s`

From the equation of motion we have that

`s =  ut + (1)/(2)  * a * t^2`

Here u = 0 because the rocket started at rest

`50 =  0 + (1)/(2) * a  * 8^2`

=>
`a =  (100)/(64)`

=>
`a =  1.5625 \ m/s^2`

Also from the kinematic equation we have that

`v  =  u + at`

=>
`v =  0 +  (8  *  1.5625)`

=>
`v =  12.5 \  m/s`