Problem 84
The great, gray-green, greasy Zambezi River flows over Victoria Falls in south central Africa. The falls are approximately \(108 \mathrm{~m}\) high. If the river is flowing horizontally at \(3.60 \mathrm{~m} / \mathrm{s}\) just before going over the falls, what is the speed of the water when it hits the bottom? Assume that the water is in free fall as it drops.
Problem 85
Playing shortstop, you pick up a ground ball and throw it to second base. The ball is thrown horizontally, with a speed of \(22 \mathrm{~m} / \mathrm{s}\), directly toward point \(A\) as shown in Figure 4.37. When the ball reaches the second baseman \(0.45 \mathrm{~s}\) later, it is caught at point B. (a) How far were you from the second baseman? (b) What is the distance of vertical drop, from \(A\) to \(B\) ?
Problem 86
A crow is flying horizontally with a constant speed of \(2.70 \mathrm{~m} / \mathrm{s}\) when it releases a clam from its beak as shown in Figure 4.38. The clam lands on the rocky beach \(2.10 \mathrm{~s}\) later. Just before the clam lands, what is (a) its horizontal component of velocity and (b) its vertical component of velocity?
Problem 87
In Denver, after Halloween, children bring their jack-o'-lanterns to the top of a tower and compete for accuracy in hitting a target on the ground, as shown in Figure 4.39. Suppose that the tower is \(9.0 \mathrm{~m}\) high and that the bull's-eye is a horizontal distance of \(3.5 \mathrm{~m}\) from the launch point. If the pumpkin is thrown horizontally, what is the launch speed needed to hit the bull's-eye?
Problem 89
A diver runs horizontally off the end of a \(3.0-\mathrm{m}\)-high diving board with an initial speed of \(1.8 \mathrm{~m} / \mathrm{s}\). (a) Given that the diver's initial position is \(x_{\mathrm{i}}=0\) and \(y_{\mathrm{i}}=3.0 \mathrm{~m}\), find her \(x\) and \(y\) positions at the times \(t=0.25 \mathrm{~s}\), \(t=0.50 \mathrm{~s}\), and \(t=0.75 \mathrm{~s}\). (b) Plot the results from part (a), and sketch the corresponding parabolic path.
Problem 90
Fairgoers ride a Ferris wheel with a radius of \(5.00 \mathrm{~m}\), as shown in Figure 4.40. The wheel completes one revolution every \(32.0 \mathrm{~s}\). (a) What is the average speed of a rider on this Ferris wheel? (b) If a rider accidentally drops a stuffed animal at the top of the wheel, where does it land relative to the base of the ride? (Note: The bottom of the wheel is \(1.75 \mathrm{~m}\) above the ground.)
Problem 91
A golfer gives a ball a maximum initial speed of \(34.4 \mathrm{~m} / \mathrm{s}\). (a) What is the longest possible hole-in-one shot for this golfer? Neglect any distance the ball might roll on the green and assume that the tee and the green are at the same level. (b) What is the minimum speed of the ball during this hole-in-one shot?
Problem 92
The hang time of a punt is measured to be \(4.50 \mathrm{~s}\). If the ball was kicked at an angle of \(63.0^{\circ}\) above the horizontal and was caught at the same level from which it was kicked, what was its initial speed?
Problem 93
A baseball player hits a high fly ball to the outfield. (a) Is there a point during the flight of the ball where its velocity is parallel to its acceleration? (b) Is there a point where the ball's velocity is perpendicular to its acceleration? Explain in each case.
Problem 94
Child 1 throws a snowball horizontally from a rooftop; child 2 throws a snowball straight down from the same rooftop. Once in flight, is the acceleration of snowball 2 greater than, less than, or equal to the acceleration of snowball 1 ?
