Ahmad throws a ball straight up. For which situation is the vertical velocity zero?
[Note: Neglect the air resistance]
Answer
at the top
on the way up
none of the above
on the way down
At the top, when the ball stops and changes direction of motion from upwards to downwards
b i a t c h
To determine the situation when the vertical velocity is zero, we need to understand how the velocity changes during the motion of the ball.
When Ahmad throws a ball straight up, the ball goes through different phases: a phase of ascending ("on the way up") and a phase of descending ("on the way down").
At the very top of the ball's trajectory, it momentarily stops moving upward before it starts moving downward. This means that as the ball reaches its highest point, the vertical velocity becomes zero. Therefore, the answer is "at the top."
To confirm this, you could solve the problem mathematically. By using the fundamental equations of motion, you would find that the vertical velocity of an object at any given point can be calculated using the equation:
v = u + a*t
Where:
- v represents the final velocity
- u represents the initial velocity
- a represents the acceleration
- t represents the time
For upward motion, the initial velocity (u) is positive and constant, while the acceleration (a) is negative due to the force of gravity. At the highest point, the final velocity (v) will be zero. Plugging in these values into the equation:
0 = u + a*t
We can conclude that when the final velocity (v) is zero, the ball is at the top of its trajectory.