Conceptual Physics

acceleration at the top of its flight path? Make sure to consider the sign when responding. Consider the upward direction as

positive.

m/s^2

3.5 The muzzle velocity of an armor-piercing round fired from an M1A1 tank is 1770 m/s (nearly 4000 mph or mach 5.2). A tank

is at the top of a cliff and fires a shell horizontally. If the shell lands 6520 m from the base of the cliff, how high is the cliff?

m

3.6 A cannon is fired horizontally from atop a 40.0 m tower. The cannonball travels 145 m horizontally before it strikes the

ground. With what velocity did the ball leave the muzzle?

m/s

3.7 A box is dropped from a spacecraft moving horizontally at 27.0 m/s at a distance of 155 m above the surface of a moon. The

rate of freefall acceleration on this airless moon is 2.79 m/s^2. (a) How long does it take for the box to reach the moon's

surface? (b) What is its horizontal displacement during this time? (c) What is its vertical velocity when it strikes the surface?

(d) At what speed does the box strike the moon?

(a) s

(b) m

(c) m/s

(d) m/s

3.8 Two identical cannons fire cannonballs horizontally with the same initial velocity. One cannon is located on a platform

partway up a tower, and the other is on top, four times higher than the first cannon. How much farther from the tower does the

cannonball from the higher cannon land than the cannonball from the lower cannon?

i. 1

ii. 2

iii. 3

iv. 4

v. 16

times farther

3.9 A ball rolls at a constant speed on a level table a height h above the ground. It flies off the table with a horizontal velocity v

and strikes the ground. Choose the correct expression for the horizontal distance it travels, as measured from the table's

edge.

i. a

ii. b

iii. c

iv. d

3.10 An archer wants to determine the speed at which her new bow can fire an arrow. She paces off a distance d from her target

and fires her arrow horizontally. She determines that she launched it at a height h higher than where it strikes the target. She

ignores air resistance. Choose an expression in terms of h,d and g that she can use to determine the initial speed of her

arrow.

(^84) Copyright 2007 Kinetic Books Co. Chapter 4 Problems