1. In outer space, where there is no gravity or air, an astronaut pushes with an equal force of 20 N on a 3 N moon rock and on a 9 N moon rock. Which statement is the most accurate about this situation?
A. Since both rocks are weightless, they will have the same acceleration.
B. Both rocks push back on the astronaut with 20 N.
C. The 9 N rock pushes back on the astronaut three times as hard as the 3 N rock.
D. Since both rocks are weightless, they do not push back on the astronaut.
Help me please.
no, they accelerate at different rates. B.
both rocks push back with 20 N, however, both are accelerating. The 20 N force is counteracted by the inertia of each rock (inertia=mass) accelerating (ma).
So A?
They may be weightless but they have mass. It is a bit misleading to say 3N rock. The implication is that it has a weight of 3N on earth where g = 9.8 m/s^2 approximately. That means that the 3 N rock has mass of 3 / 9.8 kilograms or very roughly .3 kg. Then do F = m a for the rest of the problem :)
Thank you!
To determine which statement is the most accurate about this situation, we need to understand Newton's third law of motion. According to Newton's third law, for every action, there is an equal and opposite reaction.
In this scenario, the astronaut pushes on both the 3 N and 9 N moon rocks with an equal force of 20 N. So, we know that the rocks will exert a reaction force on the astronaut.
Let's analyze each statement and see if it aligns with Newton's third law:
A. Since both rocks are weightless, they will have the same acceleration.
This statement is not accurate. Weightlessness does not affect the acceleration of an object when an external force is applied. The acceleration will depend on the mass of the object and the force applied to it. Therefore, the acceleration of the 3 N rock and the 9 N rock will not necessarily be the same.
B. Both rocks push back on the astronaut with 20 N.
This statement is also not accurate. According to Newton's third law, the rocks will exert an equal and opposite reaction force on the astronaut. So, the rocks will exert forces on the astronaut, but those forces may not necessarily be the same as the force the astronaut exerts on the rocks.
C. The 9 N rock pushes back on the astronaut three times as hard as the 3 N rock.
This statement is not accurate either. The reaction force exerted by the rocks on the astronaut will be equal and opposite to the force the astronaut applies to the rocks. Since the astronaut applies an equal force of 20 N on both rocks, the reaction forces will also be equal.
D. Since both rocks are weightless, they do not push back on the astronaut.
This statement is not accurate, as Newton's third law states that for every action, there is an equal and opposite reaction. So, the rocks will push back on the astronaut, but the magnitude of the reaction force will depend on the force applied by the astronaut.
From this analysis, we can see that none of the statements are completely accurate. However, the closest option is option B, which states that both rocks push back on the astronaut with 20 N. Although the reaction forces may not exactly equal 20 N, they will be equal in magnitude but opposite in direction to the force applied by the astronaut.