E2rev-1
(answers are on last page)
A constant force is exerted on a cart (initially at rest) on an air track.
Neglect friction.
The force acts for a short time and gives the cart a certain final speed. To
reach the same final speed with a force that is only half as big, the force
must be exerted on the cart for a time interval
A: four times as long as
C: equal to
B: twice as long as
D: half as long as
... that for the stronger force.
OR E: (Not enough information given)
E2rev-2
(answers are on last page)
5-7: An object is being lowered on a cord at a speed
which is decreasing.
There are two forces on the object, the weight
(magnitude mg) and the tension, magnitude T, in the cord.
Which equation is true:
A: T = mg
C: T < mg
T
B: T > mg
mg
(v is down, and
decreasing)
E2rev-3
(answers are on last page)
The free-body diagram for a car rounding a banked curve is shown. The
car is going so fast that it is about to slip. The coordinate system has been
chosen.
What is the correct y-equation?
A) N sin + sN cos – mg = 0
B) N –sN sin – mg cos = 0
C) N – mg cos = 0
D) N cos –sN sin – mg = 0
E) None of these
E2rev-4
(answers are on last page)
5-19: How does the force exerted on the cart by the string (T) compare
with the weight of body B?
(Assume all surfaces are frictionless)
mA
mB
A: T = mB g.
B: T < mB g.
C: T > mB g.
E2rev-5
(answers are on last page)
Two blocks, with masses M2>M1, are connected by ropes. You pull to
the right on a second rope, with external force "T1".
The blocks sit on a frictionless surface.
M2
T2
M1
T1
How do the magnitudes of the tensions in the rope compare?
A: T2 > T1
B: T2 < T1
C: T2 = T1
E2rev-6
(answers are on last page)
A glider is pulled along an air track with a string at an angle  from the
horizontal, with a constant force.
F

The direction of the net force on the glider is
A: Horizontal.
B: At an angle  above the horizontal.
C: At some angle above the horizontal, but not necessarily .
E2rev-7
(answers are on last page)
A crate of mass m is accelerated to the left with a string at an angle 
above the horizontal. The coefficient of kinetic friction is k. The
coordinate system has been chosen as shown. What is the correct y–
equation?
What is the correct y-equation?
A) F + N – mg = 0
B) Fcos –kN = ma
C) N + Fsinmg = 0
E) None of these
D) F cos –kN – mg = 0
E2rev-8
(answers are on last page)
A cart on an air track is moving at 0.5 m/s when the air is suddenly
turned off. As a result, there is friction between the cart and the track,
and the cart comes to rest after traveling 1 m. The experiment is
repeated, but now the cart is moving at 1 m/s when the air is turned off.
Assuming that the frictional force is the same in both cases, how far does
the cart travel before coming to rest?
A: Same, 1 m. B: 2 m.
C: 4 m.
E: (not enough information)
D: 1/2 m.
Hint: use the work-kinetic energy theorem
Answers:
E2rev1
E2rev2
E2rev3
E2rev4
E2rev5
E2rev6
E2rev7
E2rev8
B
B
D
B
B
A
C
C