Name:______________________________Class:__________________ Date:__________________
Assessment
Circular Motion and Gravitation
Teacher Notes and Answers
7 Circular Motion and Gravitation
CIRCULAR MOTION
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. ac = 0.83 m/s2; Fc = 1.1 103 N
Given
vt = 2.5 m/s
r = 7.5 m
m = 1.3 103 kg
Solution
b
c
a
b
c
d
b
d
Friction between the car’s tires and the road
is the centripetal force that causes the car to
move along a curved or circular path.
Passengers in the car tend to lean or slide
toward the outside of the turn because their
inertia causes them to tend toward moving
in a straight-line path.
vt 2 (2.5 m/s) 2
=
= 0.83 m/s 2
r
7.5 m
mvt 2 (1.3 103 kg )(2.5 m/s) 2
Fc =
=
r
7. 5 m
= 1.1 103 N
ac =
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Physics
1
Section Quizzes
Name:______________________________Class:__________________ Date:__________________
Assessment
Circular Motion and Gravitation
Section Quiz: Circular Motion
Write the letter of the correct answer in the space provided.
_____ 1. Centripetal acceleration must involve a change in
a. an object’s tangential speed.
b. an object’s velocity.
c. both an object’s speed and direction.
d. the radius of an object’s circular motion.
_____ 2. What is the speed of an object in circular motion called?
a. circular speed
b. centripetal speed
c. tangential speed
d. inertial speed
_____ 3. Which of the following is the correct equation for centripetal
acceleration?
2
v
a. ac = t
r
vt
b. ac =
r
2
mvt
c. ac =
r
(vt, f – vt,i )
d. ac =
t
_____ 4. What is the centripetal acceleration of a skater moving with a tangential
speed of 2.0 m/s in a circular path with radius 2.0 m?
a. 1.0 m/s2
b. 2.0 m/s2
c. 4.0 m/s2
d. 8.0 m/s2
_____ 5. What term describes a force that causes an object to move in a circular
path?
a. circular force
b. centripetal acceleration
c. centripetal force
d. centrifugal force
_____ 6. A centripetal force acts
a. in the same direction as tangential speed.
b. in the direction opposite tangential speed.
c. perpendicular to the plane of circular motion.
d. perpendicular to tangential speed but in the same plane.
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Physics
2
Section Quizzes
Name:______________________________Class:__________________ Date:__________________
Circular Motion and Gravitation continued
_____ 7. Centripetal force can be calculated from centripetal acceleration by
a. dividing by the mass.
b. multiplying by the mass.
c. squaring the acceleration and dividing by the radius.
d. squaring the acceleration, multiplying by the mass, and dividing by
the radius.
_____ 8. Which of the following is due to inertia?
a. A ball whirled in a circular motion stays in one plane.
b. A ball whirled in a circular motion experiences centripetal
acceleration directed toward the center of motion.
c. A ball whirled in a circular motion experiences a centripetal force
directed toward the center of motion.
d. A ball whirled in a circular motion will move off in a straight line if
the string breaks.
9. Describe the primary force or forces involved when a car executes a turn.
Explain why passengers tend to lean or slide toward the outside of the turn.
_________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
10. A 1.3 103 kg car traveling with a speed of 2.5 m/s executes a turn with a
7.5 m radius of curvature. Calculate the centripetal acceleration of the car and
the centripetal force acting on the car.
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Physics
3
Section Quizzes