Chapter 4

As you walk briskly down the street, you toss a small ball into the air. (a) If you want the ball to land in your hand when it comes back down, should you toss the ball straight upward, in a forward direction, or in a backward direction? (b) Choose the best explanation from among the following: A. If you throw the ball straight up, you will leave it behind. B. You have to throw the ball in the direction in which you are walking. C. The ball moves in the forward direction at your walking speed at all times.

Two divers run horizontally off the edge of a low cliff. Diver 2 runs with twice the speed of diver 1. (a) When the divers hit the water, is the horizontal distance covered by diver 2 twice as much as, four times as much as, or equal to the horizontal distance covered by diver 1? (b) Choose the best explanation from among the following: A. The drop time is the same for both divers. B. Drop distance depends on \(t^{2}\). C. All divers in free fall cover the same distance.

A quarterback can throw a receiver a high, lazy lob pass or a low, quick bullet pass. These passes are indicated by curves 1 and 2 , respectively, in Figure 4.43. (a) The lob pass is thrown with an initial speed of \(21.5 \mathrm{~m} / \mathrm{s}\), and its time of flight is \(3.97 \mathrm{~s}\). What is its launch angle? (b) The bullet pass is thrown with a launch angle of \(25.0^{\circ}\). What is the initial speed of this pass? (c) What is the time of flight of the bullet pass?

Write a report on the maximum range of a projectile. Address the following questions: How does the launch angle for maximum range depend on whether the projectile lands at a level that is higher or lower than its launch level? How is the angle for maximum range affected by air resistance?

You drop a set of keys as you walk down the street. Do the keys land behind you or right at your feet? Is the drop time of the keys affected by your forward motion? Is the acceleration of the keys affected by your forward motion? Explain.