Section 9 - Interactive problem: the monkey and the professor, part II
9.1 Using the simulation in the interactive problem in this section, where should the monkey aim the bazooka? Why?
i. Above the professor's glove
ii. At the professor's glove
iii. Below the professor's gloveSection 10 - Projectile motion: aiming a cannon
10.1 A long jumper travels 8.95 meters during a jump. He moves at 10.8 m/s when starts his leap. At what angle from the
horizontal must he have been moving when he started his jump? You may need the double-angle formula:
2 sin u cos u = sin (2u)
°
10.2 Your projectile launching system is partially jammed. It can only launch objects with an initial vertical velocity of 42.0 m/s,
though the horizontal component of the velocity can vary. You need your projectile to land 211 m from its launch point. What
horizontal velocity do you need to program into the system?
m/s
10.3 A professional punter can punt a ball so that its "hang time" is 4.20 seconds and it travels 39.0 m horizontally. State its initial
velocity in rectangular coordinates. Ignore air resistance, and assume the punt receiver catches the ball at the same height at
which the punter kicks it.
( , ) m/s
10.4 A home run just clears a fence 105 m from home plate. The fence is 4.00 m higher than the height at which the batter struck
the ball, and the ball left the bat at a 31.0° angle above the horizontal. At what speed did the ball leave the bat?
m/s
10.5 You are the stunt director for a testosterone-laden action movie. A car drives up a ramp inclined at 10.0° above the
horizontal, reaching a speed of 40.0 m/s at the end. It will jump a canyon that is 101 meters wide. The lip of the takeoff ramp
is 201 meters above the floor of the canyon. (a) How long will the car take to cross the canyon? (b) What is the maximum
height of the cliff on the other side so that the car lands safely? (c) What angle with the horizontal will the car's velocity make
when it lands on the other side? Assume the height of the other side is the maximum value you just calculated. Express the
angle as a number between í180° and +180°.
(a) s
(b) m
(c) °
10.6 The infamous German "Paris gun" was used to launch a projectile with a flight time of 170 s for a horizontal distance of
122 km. Based on this information, and ignoring air resistance as well as the curvature of the Earth, calculate (a) the gun's
muzzle speed and (b) the angle, measured above the horizontal, at which it was fired.(a) m/s
(b) °
10.7 At its farthest point, the three-point line is 7.24 meters away from the basket in the NBA. A basketball player stands at this
point and releases his shot from a height of 2.05 meters at a 35.0 degree angle. The basket is 3.05 meters off the ground.
The player wants the ball to go directly in (no bank shots). At what speed should he throw the ball?
m/s
10.8 You and your friend are practicing pass plays with a football. You throw the football at a 35.0° angle above the horizontal at
19.0 m/s. Your friend starts right next to you, and he moves down the field directly away from you at 5.50 m/s. How long after
he starts running should you throw the football? Assume he catches the ball at the same height at which you throw it.
s
10.9 If there were no air resistance, how fast would you have to throw a football at an initial 45° angle in order to complete an 80
meter pass?
m/s
10.10A soccer ball is lofted toward the goal from a distance of 9.00 m. It has an initial velocity of 12.7 m/s and is kicked at an angle
of 72.0 degrees above the horizontal. (a) When the ball crosses the goal line, how high will it be above the ground? (b) How
long does it take the ball to reach the goal line? (It will still be in the air.)
(a) m
(b) s(^86) Copyright 2007 Kinetic Books Co. Chapter 4 Problems