Question

A 500 g model rocket accelerates from 20 m/s [up] to 45 m/s [up] in 0.70 is the net force acting on the rocket? assuming that the change in mass of the rocket is negligible (very little fuel used up), determine the magnitude of the thrust force that propels the rocket upward.

A) 357 N
B) 214 N
C) 71 N
D) 143 N

Answer 1

The net force acting on the rocket is 17.86 N and the magnitude of the thrust force is also 17.86 N.

Step-by-step explanation:

In order to determine the net force acting on the rocket, we can use Newton's second law of motion, which states that the net force is equal to the mass of an object multiplied by its acceleration:

Fnet = m * a

Given that the mass of the rocket is 500 g (0.5 kg) and the change in velocity is from 20 m/s up to 45 m/s up, the acceleration can be calculated as:

a = (v - u) / t = (45 - 20) / 0.7 = 25 / 0.7 = 35.71 m/s^2

Therefore, the net force acting on the rocket can be calculated as:

Fnet = m * a = 0.5 kg * 35.71 m/s^2 = 17.86 N

Since the change in mass of the rocket is negligible, the thrust force that propels the rocket upward is equal to the net force acting on the rocket:

Thrust force = 17.86 N