Question

A rocket with mass m=5kg is launched into the air. the rocket engine 25,000j of work before it stops burning and the rocket reaches a mac height h=180 m what is the speed of the rocket when it reaches its max height . B what is the rocket speed when it hits the ground again c what maximum height would the rocket reach if it had been launched straight up

Answer 1

We are going to solve the given problem using conservation of energy principle. According to which, the total energy of a isolated system remains constant.

Now, the total energy given to the rocket,

E= Work done by the rocket=25000 Joules (given)

Now, the potential energy of the rocket of mass 'm' at a height 'h' is

Acceleration due to gravity

And the kinetic energy of the rocket at velocity 'v' is

So, according to conservation of mechanical energy,

Now, given m=5kg

(A)

At height, ,

(B)

When the rocket hits the ground, h=0.

(C)

If the rocket is lunched straight up, at the maximum height, velocity