An object is thrown vertically upward.
a) What are its velocity and acceleration when it reaches its highest altitude?
b) What is its acceleration on its way downward half a meter above the ground?
My ans:
a) velocity is zero and acceleration is 9.8 m/s^2
b) i am not sure but i think acceleration should still be 9.8m/s^2
a) When the object reaches its highest altitude, its velocity is zero because it momentarily stops before falling back down. The acceleration at this point is still 9.8 m/s^2, directed downwards due to gravity.
b) Half a meter above the ground, the object is on its way downward. The acceleration at this point is still 9.8 m/s^2, but now directed upwards since the object is decelerating as it moves against the direction of gravity. This can be quite a shocking experience for the object, going against the natural order of things. It's like trying to drink coffee through a straw but having the coffee suddenly shoot back into the mug.
Your answer for part a) is correct. When the object reaches its highest altitude, its velocity becomes zero and its acceleration remains constant at 9.8 m/s^2, which is the acceleration due to gravity.
For part b), when the object is halfway downward (half a meter above the ground), the acceleration is still 9.8 m/s^2 in the downward direction. The acceleration remains the same throughout the entire motion, whether the object is moving upward or downward.
To determine the velocity and acceleration of the object at various points, we can apply the laws of motion. Let's break down each part of the question and use the kinematic equations:
a) When the object reaches its highest altitude, its velocity would be zero, as the object momentarily stops before reversing its direction. Acceleration would still be present, and in this case, the acceleration due to gravity is always directed downwards, with a magnitude of approximately 9.8 m/s^2.
b) To determine the acceleration of the object when it is half a meter above the ground on its way downward, we can still use the acceleration due to gravity. When the object is close to the ground, assuming it is in free fall, the acceleration would remain constant, which is approximately 9.8 m/s^2.
Therefore, your initial answer for part a) is correct: the velocity is zero, and the acceleration is 9.8 m/s^2. For part b), your intuition is also correct in assuming that the acceleration is still 9.8 m/s^2.