(a) i. F
ii. -F
iii. 0
iv. -F/2
v. F/2
(b) i. F
ii. -F
iii. 0
iv. -F/2
v. F/2
(c) i. F
ii. -F
iii. 0
iv. -F/2
v. F/2
C.13From the example of the falling cat, we see that the cross-sectional area of a falling object affects its terminal velocity. Does
an object's mass also affect its terminal velocity? Why or why not?Yes NoSection Problems
Section 0 - Introduction
0.1 Use the simulation in the interactive problem in this section to answer the following question. If the net force on the helicopter
is zero, what must the helicopter be doing?
i. Rising
ii. Falling
iii. Staying still
iv. It can be doing any of theseSection 2 - Newton’s first law
2.1 An airplane of mass 2867 kg flies at a constant horizontal velocity. The force of air resistance on it is 2225 N. What is the net
force on the plane (magnitude and direction)?
i. 0 N (direction does not matter)
ii. 2225 N opposing the motion
iii. 642 N at 30° below horizontal
iv. It is impossible to say
2.2 Three children are pulling on a toy that has a mass of 1.25 kg. Child A pulls with force (5.00, 6.00, 2.50) N. Child B pulls with
force (0.00, 9.20, 2.40) N. With what force must Child C pull for the toy to remain stationary?
( , , ) NSection 4 - Gravitational force: weight
4.1 A weightlifter can exert an upward force of 3750 N. If a dumbbell has a mass of 225 kg, what is the maximum number of
dumbbells this weightlifter could hold simultaneously if he were on the Moon? (The Moon's acceleration due to gravity is
approximately 0.166 times freefall acceleration on Earth.) The weightlifter cannot pick up a fraction of a dumbbell, so make
sure your answer is an integer.
dumbells
4.2 (a) How much does a 70.0 kg person weigh on the Earth? (b) How much would she weigh on the Moon (gmoon = 0.166g)? (c)
How much would she weigh on a neutron star where gstar = 1.43×10^11 g?(a) N
(b) N
(c) N
4.3 A dog weighs 47.0 pounds on Earth. (a) What is its weight in newtons? (One newton equals 0.225 pounds.) (b) What is its
mass in kilograms?
(a) N
(b) kg(^114) Copyright 2007 Kinetic Books Co. Chapter 5 Problems