Final answer:
The velocity of an object thrown straight up is zero at its highest point, its velocity does change direction as it falls back down, and the acceleration due to gravity is constant at 9.8 m/s² and remains in the same direction, downward, throughout the object's ascent and descent.
The correct option is; a) (a) At the top. (b) Yes. (c) No.
Step-by-step explanation:
When analyzing one-dimensional motion involving gravity, it's important to consider the characteristics of an object's motion as it is thrown straight up and then falls back to Earth. The key components of this motion are velocity and acceleration due to gravity.
(a) The velocity of the object is zero at the highest point of its trajectory. This is the moment when the object has stopped moving upward and is about to begin its descent.
(b) The velocity does indeed change direction. Initially, the object moves upwards, and after reaching its highest point, it begins to move downwards.
(c) The acceleration due to gravity has the same magnitude and direction throughout the entire motion. On the way up, the acceleration due to gravity is directed downwards and works against the upward motion of the object, slowing it down. On the way down, it accelerates the object towards the Earth.
This acceleration is constant and has a typical value of 9.8 m/s² downward, irrespective of the object's motion direction.