Question

A bit confused on how to solve this

For each indicated point on the trajectory, place the vectors that qualitatively represent the relative velocity Uy and acceleration ay of a ball that is thrown straight up, from the time it is thrown to the time it is caught. Note that the horizontal displacement of the ball is only for visual clarity. The vector for the acceleration due to gravity is at the bottom of the figure for reference. Answer Bank -g

Answer 1

This is actually very simple. All you need to know is the direction of velocity of ball at each moment, as well as the direction of acceleration.

• The direction of vertical velocity will be upwards until it reaches the maximum height (velocity decreases gradually as moving from bottom to the top, with maximum velocity at the bottom and minimum at the top).
• From there on wards, as the ball falls down, The direction of vertical velocity will be downwards. (velocity increases gradually as moving from top to the bottom, with maximum velocity at the bottom and minimum at the top).
• Acceleration is constant in magnitude and always directed downwards. Note that, we need to choose the same length of vector for g shown in the reference figure as shown below:

-zero velocity *g will be always downward