Projectile Motion Physics 513

What You “Should” Have Seen

Let’s Apply What We’ve Learned A motorcycle stunt rider rides off the edge of a cliff. Just at the edge his velocity is horizontal, with magnitude 9.0 m/s. Find the motorcycle’s position, displacement from the edge of the cliff, and velocity 0.50 s after it leaves the edge of the cliff

You Don’t Always Get Numbers… In a local establishment, a customer slides an empty mug down the counter for a refill. The bartender is momentarily distracted and does not see the mug, which slides off the counter and strikes the floor at distance d from the base of the counter. The height of the counter is h. (a) With what velocity did the mug leave the counter, and (b) what was the direction of the mug’s velocity just before it hit the floor?

Angled Projectile Motion  

Let’s Apply What We’ve Learned Suppose you are running at constant velocity and you wish to throw a ball such that you will catch it as it comes back down. In what direction should you throw the ball relative to you? (a) straight up (b) at an angle to the ground that depends on your running speed (c) in the forward direction

Let’s Up the Difficulty A placekicker attempts a field goal from 11 m away. The bar is 3 m above the ground. (a) If the ball is kicked at 45.0° above the horizontal, what must its initial speed be if it is to just clear the bar? ANS: 12.2 m/s (b) There is a minimum angle above the ground such that if the ball is launched below this angle, it can never clear the bar, no matter how fast it is kicked. What is this angle? ANS: 15.3