Question

A second toy rocket did 800 Nm of work to reach a height of 20m. What is the mass of the rocket?

A) 4.08 kg

B) 40.81 kg

C) 6.39 kg

D) 40 kg

Answer 1

4.08Kg

Step-by-step explanation:

work done = force. displacement

800Nm = 20×force

force = 800/20

force 40

we know that F = mass × acceleration

acceleration = 9.8m/s²

40/9.8. = mass

mass of body = 4.081 kg

Answer 2

We can use the formula for potential energy to solve this problem:

Potential energy = mass x gravity x height

The work done by the rocket is equal to the change in potential energy, which is given by:

Work = potential energy at final height - potential energy at initial height

Since the rocket starts from rest on the ground, the initial potential energy is zero. Therefore, the work done by the rocket is equal to the potential energy at the final height:

Work = potential energy at final height = mgh

where m is the mass of the rocket, g is the acceleration due to gravity (9.8 m/s^2), and h is the height reached by the rocket (20 m).

Substituting the given values, we get: 800 Nm = m x 9.8 m/s^2 x 20 m

Solving for m, we get: m = 800 Nm / (9.8 m/s^2 x 20 m) = 4.08 kg

Therefore, the mass of the rocket is 4.08 kg.


Answer: A) 4.08 kg