Question

While juggling, you throw a red ball straight up and it returns to your hand 4.00 s later. You throw a blue ball to the same height but at an angle 60° from the horizontal axis. What speed did you throw the blue ball to get it to the same height as the red ball?

A. 9.8 m/s
B. 19.6 m/s
C. 29.4 m/s
D. 39.2 m/s

Answer 1

To get the blue ball to the same height as the red ball, you need to throw it at an initial velocity of 9.8 m/s.

Step-by-step explanation:

To find the speed at which you need to throw the blue ball to get it to the same height as the red ball, we need to consider the vertical motion of both balls.

For the red ball, we know that it takes 4.00 s to go up and come down. Since the time of flight is the same for both the red and blue ball, the time for the blue ball to reach the maximum height is also 4.00 s.

Using the equation s = ut + (1/2)gt^2, where s is the vertical displacement, u is the initial velocity, t is the time, and g is the acceleration due to gravity, we can calculate the initial velocity of the blue ball.

Since the blue ball is thrown at an angle of 60° from the horizontal, the vertical component of its initial velocity would be u*sin(60°), which is equal to the initial velocity of the red ball.

Therefore, the speed at which you need to throw the blue ball is the initial velocity of the red ball, which is 9.8 m/s (option A).