Question

please quick quick help on this physics questionn please I only got 20 minutes pleasee

Question 1: An astronaut is moving in space (gravity is negligible). He finds that the closer he gets to a mysterious object in space, the more a force of repulsion he feels the object is exerting on his ship. Using Newton's 3rd Law of motion, what can he say about the motion of the mysterious object, assuming its interacting only with the ship? What's the difference between dynamics and kinematics? What is the law that connects them? I In profectile motion, why do we use g as the acceleration in the y-direction? Why do we add a minus sign in front of it?

Answer 1

The more the astronaut gets closer to object, the more repulsive force the object exerts on his ship. By Newton's third law, we can say that as the astronaut gets closer to object, the ship also exerts a larger repulsive force on the object. The force is equal in magnitude and opposite in direction to the force experienced by the ship.

While kinematics is the study of motion of an object, dynamics is the study of cause of that motion of the object. Newton's second law (F = ma) relates the two.

The only force acting on object during projectile motion is the force of gravity (mg). Hence the acceleration is g only in the y-direction. We put a minus sign because this g always points vertically downwards ( negative y).

1 + 1 = 3 is False.