Assessment
Forces and the Laws of Motion
Teacher Notes and Answers
4 Forces and the Laws of Motion
NEWTON’S FIRST LAW
1.
2.
3.
4.
5.
6.
7.
8.
9.
d
a
d
c
d
b
d
c
The net force has not changed because the
pillow is still at rest.
10. 215 N
Given
Fg = 165 N
θ = 50.0°
Solution
Fnet , y =∑ Fy = Fg – Fapplied , y =0
Fapplied , y = Fg
Fapplied =
Fapplied , y
=
Fg
sin θ
sinθ
(165 N)
=
= 215 N
(sin 50.0°)
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Holt McDougal Physics
Section Quiz
Name: _____________________________ Class: __________________Date: __________________
Assessment
Forces and the Laws of Motion
Section Quiz: Newton’s First Law
Write the letter of the correct answer in the space provided.
_____ 1. Which of the following situations describes inertia?
a. A stationary object tends to resist being moved.
b. A moving object tends to resist a change in speed.
c. A moving object tends to resist a change in direction.
d. all of the above
_____ 2. Which of the following is true of inertia?
a. It is described in Newton’s first law of motion.
b. It is a property of motion.
c. It is measured by weight.
d. all of the above
_____ 3. Two forces act on an object. The magnitude of the net force acting on
the object
a. equals the sum of the magnitudes of the two forces.
b. equals the difference in the magnitudes of the two forces.
c. equals the average of the two forces.
d. cannot be determined from the given information.
_____ 4. An object is at rest on an incline. The component of gravity acting
downward and along the incline on the object is described as
Fg, x = +8.0 N. Which axis is pointing up the incline?
a. +x-axis
b. +y-axis
c. −x-axis
d. −y-axis
_____ 5. A force of 5 N and a force of 15 N acting on an object can produce the
following net forces except
a. 20 N.
c. 10 N.
b. 15 N.
d. 5 N.
_____ 6. Two dogs are tugging on a toy. One dog pulls with a horizontal force of
14 N due north. The other is pulling due east with a horizontal force
of 14 N. What is the direction of the net external horizontal force on the
toy?
a. north
b. northeast
c. west
d. northwest
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Physics
1
Section Quiz
Name: _____________________________ Class: __________________Date: __________________
Forces and the Laws of Motion continued
_____ 7. Which of the following statements describe an object in equilibrium?
I. The object is at rest.
II. The object is moving at constant velocity.
III. The net external force on the object is zero.
a. I and II
b. I and III
c. II and III
d. I, II, and III
_____ 8. A single force acting on an object is represented in a free-body diagram
of the object by the following force vector: ↑. Which of the following
force vectors represents a single force acting on the object that will
bring the object into equilibrium?
a. ↑
b. →
c. ↓
d. ←
9. While sitting in a lounge chair with the back inclined at an angle of 10° from
the vertical, you tuck a pillow between your head and the chair. Then you
lower the chair back to 40° and doze with the pillow in place. How has the net
force on the pillow changed?
______________________________________________________
______________________________________________________
10. A rigid rod holds a restaurant sign horizontally from the side of a building.
The force due to gravity acting on the sign is 165 N with the angle between the
sign and the rod being 50.0°. Ignoring the weight of the rod, what is the
magnitude of the tension in the rod?
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Physics
2
Section Quiz