A tennis ball is thrown vertically upward with an initial velocity of +7.0 m/s.
What will the ball’s velocity be when it returns to its starting point? The acceleration of gravity is 9.81 m/s^2.
Answer in units of m/s
+7.0 m/s. Throwing something is always parabolic; when the ball reaches the distance it began at (remember, it peaks at velocity = 0 m/s) it has the original velocity.
To determine the ball’s velocity when it returns to its starting point, we need to analyze the motion of the ball. We know that the initial velocity when it is thrown upward is +7.0 m/s and the acceleration due to gravity is -9.81 m/s^2 (negative because it acts downward). The negative sign indicates that the acceleration is in the opposite direction to the initial velocity.
Since the ball is thrown upward and eventually returns to its starting point, we can infer that its final velocity is zero when it reaches that point. This is because the ball reaches its highest point and starts to fall back down, momentarily coming to a stop.
To find the final velocity, we can use the kinematic equation:
v^2 = u^2 + 2as
where v is the final velocity, u is the initial velocity, a is the acceleration, and s is the displacement.
Since the displacement when the ball returns to its starting point is zero, we can substitute s = 0 into the equation:
v^2 = u^2 + 2as
0 = u^2 + 2a(0)
0 = u^2
Therefore, the final velocity of the ball when it returns to its starting point is 0 m/s.