Question

A model rocket is constructed with a motor that can provide a total impulse of 25.0 N·s. The mass of the rocket is 0.203 kg. What is the speed that this rocket achieves when it is launched from rest? Neglect the effects of gravity and air resistance.

Answer 1

Answer:

v = 123.15 m/s

Explanation:

It is given that,

Total impulse provided by the model rocket, J = 25 N.s

Mass of the rocket, m = 0.203 kg

To find,

The speed with which it was launched

Solve,

According to Impulse- momentum theorem, the relationship between the impulse and the momentum is given by :

$J=F.t=m\Delta v$

$J=F.t=m(v-u)$ (u = 0 at rest)

$J=mv$

$v=\dfrac{J}{m}$

$v=\dfrac{25\ N.s}{0.203\ kg}$

v = 123.15 m/s

Therefore, the speed of the rocket when it was launched is 123.15 m/s.

Answer 2

Answer:

123.15 m/s

Explanation:

Impulse = 25 Ns

mass of rocket, m = 0.203 kg

Initial velocity of rocket, u = 0 m/s

Let the rocket achieved the speed of v.

Impulse = change in momentum

Impulse = m (v - u)

25 = 0.203 (v - 0)

25 = 0.203 v

v = 123.15 m/s

Thus, the rocket achieved the speed of 123.15 m/s.