Transcript Chapter6Clickers

Physics of Everyday Phenomena
W. Thomas Griffith
Juliet W. Brosing
Chapter 6
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Question 6.1
A crate is being pushed with a constant horizontal
force, F. Four forces can be identified: 1) F, 2) the
gravitational force, 3) the normal force, and 4) the
frictional force. Which forces do NO work on the
crate?
A) 1 & 4
B) 2 & 3
C) 2 & 3 & 4
D) 1 & 2 & 3
Question 6.2
If an equivalent amount of work is done in a
shorter period of time
A) more power is required
B) the same amount of power is required
C) less power is required
Question 6.3
If objects A and B have the same mass, but
object B has 9X the kinetic energy of object
A, what is true of their speeds?
A) vB = 9vA
B) vB = 3vA
C) 9vB = vA
D) 3vB = vA
Question 6.4
Compare the kinetic energy of two balls:
ball 1: mass m thrown with speed 2v
ball 2: mass 2m thrown with speed v
A)
B)
C)
D)
KE1 = 4KE2
KE1 = KE2
2KE1 = KE2
KE1 = 2KE2
Question 6.5
A cart starts with velocity v and rolls up the
frictionless path shown. At what point is the
kinetic energy greatest?
A) 1
B) 2
C) 3
D) 4
Question 6.6
A truck, initially at rest, rolls down a frictionless
hill and attains a speed of 20 m/s at the
bottom. To achieve a speed of 40 m/s at the
bottom, how many times higher must the hill
be?
A) half the height
B) the same height
C) 12 times the height
D) twice the height
E) four times the height
Question 6.7
Potential energy is energy that an object
possesses because of its
A) position
B) motion
C) temperature
D) conductivity
Question 6.8
A cart starts with velocity v and rolls up the
frictionless path shown. At what point is the
potential energy greatest?
A) 1
B) 2
C) 3
D) 4
Question 6.9
If the height of an object above a reference
level is quadrupled its gravitational potential
energy is multiplied by
A) 16
B) 4
C) 1/4
D) 1/16
Question 6.10
Suppose that a given amount of work is
required to crush an aluminum can and you
can crush a can by dropping a rock on it
from height h on the Earth. On the moon,
from approximately what height must you
drop the same rock to crush a can?
A) h
B) 3h
C) 6h
D) 9h
Question 6.11
Suppose that you can crush an aluminum can by
dropping a rock of mass m on it from a
height h. Which of the following scenarios
would crush two cans?
A) dropping a rock of mass 2m from height h
B) dropping a rock of mass m from height 2h
C) dropping a rock of mass 1/2m from height 4h
D) all of the above
E) none of the above
Question 6.12
The principle of conservation of energy states that if
the total mechanical energy is a constant then
A) the momentum is always a constant
B) no work is done on a system by any
nonconservative forces
C) no work is done on a system by any forces
D) work is done on a system in order to conserve
energy
Question 6.13
A cart starts with velocity v and rolls up the
frictionless path shown. At what point does
the cart have the greatest total energy?
A) 1
B) 2
C) 3
D) 4
E) all the same
Question 6.14
Can the total mechanical energy
E = KE + PE ever be negative ?
A) Yes, always.
B) Yes, because KE can be negative.
C) Yes, because PE can be negative.
D) No.
Question 6.15
Which path correctly indicates the motion of the pendulum bob after the
string is cut when the pendulum is at the bottom of its swing?
A. A
B. B
C. C
Question 6.16
Which path correctly indicates the motion of the pendulum bob when it is cut
at the instant it is at the top of its swing?
A. A
B. B
C. C
D. D
Question 6.17
If the distance a spring is stretched from its
equilibrium position is halved the potential
energy of the spring is multiplied by
A) 4
B) 2
C) 0.5
D) 0.25
Question 6.18
Simple harmonic motion
A) occurs when there are no forces on the
system
B) requires a constant force
C) requires a force which is not constant,
but varies directly with position
D) requires a force which is not constant,
but varies inversely with position
Question 6.19
A mass suspended from a spring
moves with the greatest velocity
A) at the end points of its motion
B) at the equilibrium position
C) midway between the end point
of its motion and the equilibrium
position
Answer Key to Chapter 6
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
B
A
B
D
A
E
A
D
B
C
11)
12)
13)
14)
15)
16)
17)
18)
19)
D
B
E
C
C
B
D
C
B