Go Pro!

Leonard and William

Pro Problems > Physics > Motion and Forces > Projectile Motion

Leonard and William

Leonard and William each received ping pong ball launchers for Christmas. The launchers are identical, and have a muzzle velocity of 16
*. Leonard aims his upward at a 30 degree angle of inclination, and fires toward William. William waits one second, and then fires his launcher horizontally toward Leonard. Both fired from the same height. The two ping pong balls collide in midair. How far apart are Leonard and William standing?

BONUS: What can we conclude about the height at which the ping pong balls were fired?

* 16
is approximately 36 mph, so these are clearly Starfleet issue ping pong ball launchers. Don't ask Santa for one of these.

Presentation mode
Problem by Mr. Twitchell


In order to make it feasible for teachers to use these problems in their classwork, no solutions are publicly visible, so students cannot simply look up the answers. If you would like to view the solutions to these problems, you must have a Virtual Classroom subscription.
Assign this problem
Click here to assign this problem to your students.

Similar Problems

Horizontal Launch

A cannonball is fired from a cannon, at a height of 3 feet from the ground.

The cannonball travels 80 yards before hitting the ground.  At what speed is the cannonball traveling when it hits the ground?

Airplane Drop

A jet is traveling at 250
, and a box is dropped from its cargo bay. Assuming that the jet is traveling at a height of 12,000 m, and there is neither wind nor air resistance, how far (horizontally) will the object travel from its drop point before hitting the ground?

Speeding Bullet

Two bullets are fired horizontally from two different guns. The first bullet has an initial velocity of 150
.  The second bullet has an initial velocity of 200
. Assuming both are fired horizontally from a height of 1.5 meter, and air friction is negligible, how much further will the second bullet travel than the first before hitting the ground?

Baling Hay

A hay baler shoots bales of hay out at a 30 degree angle. The bale of hay rises to a height of 3 feet above its launch position before it begins to fall. How far did the bale travel horizontally in that time?

Decelerating Jet

A jet is traveling at a speed of 250
, and is decelerating at a rate of 2
.  The jet maintains a constant height of 10,000 meters.

Someone has marked an X on the ground 15000 meters ahead of the jet's current location.

If cargo is to be dropped in order to land exactly on the X, and we assume no air/wind resistance, how many seconds should they wait before dropping the cargo?

Santa's Present Drop

Because of union troubles at the North Pole, Santa has to cut corners in his operation. One of the ways he's cutting corners this year is as follows: at every house, he will swoop down to 0.5 meter above the top of each chimney, and just as he's passing over the edge of the roof, he will drop presents from his sleigh, so they will fall down the chimney.

This will save him the time and trouble of climbing down chimneys (plus, Mrs. Claus likes it because he doesn't have as much cookies and milk this way).

However, there is a problem with the new system. Everyone's chimney must be the same distance from the edge of the roof. If Santa's sleigh travels at 40
, and you are a contractor building a house, how far from the edge will you place the chimney, so that presents won't get stuck on the roof?

Hunting on a Hill

Horace the Hunter is standing on a hillside facing toward the summit of the hill.  The hill has an angle of inclination of 10 degrees. Horace fires his gun horizontally from a height of 4 feet off the ground. If his gun has a muzzle velocity of 2,000
, what is the horizontal distance the bullet will travel before striking the ground?

Flight of the Roaster Chicken

Sometimes Physics problems happen in the strangest of circumstances. This morning my wife and children went grocery shopping. One child sat in the seat in the back of the grocery cart, and the other sat in the cute little "toy car" at the front of the cart. Today a roaster chicken was being purchased. In the process of putting the bird in the cart, my wife fumbled it, and then fumbled it again, and after bouncing from one hand to the other, it launched outward, and went through the window of the toy car, to land in the passenger seat next to my son.

We estimated the following information:

  • After the fowl was fumbled, it flew out of my wife's hand in a horizontal manner.
  • The poor creature traveled a horizontal distance of about 2 feet before joining my son in the cart.
  • The vertical distance between the bird bobble and its berth was about 3 feet.

Based on this information, how fast was the bird flying when it hit the seat? Give your answer in miles per hour.

Projectile with Air Resistance

A bullet is fired horizontally from a gun with an initial velocity of 600 ft/s.  Wind resistance causes a horizontal acceleration of -2 ft/s2.  If the bullet is 4 feet off the ground when it is fired, how far will it travel before striking the ground?

Roof Launch

A roof has a slope of 20 degrees, and a length of 20 meters. A box slides down the roof from the peak (assume a coefficient of kinetic friction of 0.15), until it reaches the edge of the roof. At this point, it falls 10 meters to the ground. How far from the building will the box land?

Slingshot Launch, You Sank My Battleship!

Blogs on This Site

Reviews and book lists - books we love!
The site administrator fields questions from visitors.
Like us on Facebook to get updates about new resources
Pro Membership