Projectile Motion - Example Problem 3.2-7

 

A pitcher throws a baseball horizontally with a speed of 90 mph from a height of 6 ft. If the batter is 60 ft away, determine the time needed for the ball to arrive at the batter and the height H at which it passes the batter.

 

 

Given:

• v_xo = 90 mph = 132 ft/s
• v_yo = 0
• y_A = 6 ft
• x_B = 60 ft

 

Find:

• t_B
• H

 

Video solution:

 

The following video walks you through the solution to this problem. It is suggested that you try solving the problem first and then, if you have difficulties with the solution, watch the video for help.

 

 

Interactive solution:

 

When solving projectile problems, it is a good idea to label the important points of motion (e.g. the start, the apex, the end).

 

Click on the figure to see how this problem was labeled.

 

It is usually a good strategy to start analyzing a projectile problem in the x-direction.

 

Use the x-direction equation to solve for t_B.

 

t_B = s