Download Practice_test_2_short (Chapters 6

Seat number______
Midterm 2 – Multiple choice and short answers
(Chapters 6-10)
Multiple choice part
1. A split highway has a number of lanes for traffic. For traffic going in one direction,
the radius for the inside of the curve is half the radius for the outside. One car,
car A, travels on the inside while another car of equal mass, car B, travels at equal
speed on the outside of the curve. Which statement about resultant forces on the
cars is correct?
a.
b.
c.
d.
e.
2.
A student is sitting on the right side of a school bus when it makes a right turn.
We know that the force of gravity acts downwards and a normal force from the
seat acts upwards. If the student stays in place when the bus turns, we also know
that there must be
a.
b.
c.
d.
e.
3.
The force on A is half the force on B.
The force on B is half the force on A.
The force on A is four times the force on B.
The force on B is four times the force on A.
There is no net resultant force on either as long as they stay on the road
while turning.
no other force on the student.
a force parallel to the seat directed forward on the student.
a force parallel to the seat directed to the left on the student.
a force parallel to the seat directed to the right on the student.
a force parallel to the seat in a direction between forward and left on the
student.
When a car goes around a circular curve on a level road,
a.
b.
c.
d.
e.
no frictional force is needed because the car simply follows the road.
the frictional force of the road on the car increases when the car’s speed
decreases.
the frictional force of the road on the car increases when the car’s speed
increases.
the frictional force of the road on the car increases when the car moves to
the outside of the curve.
there is no net frictional force because the road and the car exert equal and
opposite forces on each other.
-24. A rock attached to a string swings in a vertical circle. Which free body diagram could
correctly describe the force(s) on the rock when the string is in one possible
horizontal position?
5.
Inspect the four Force F(x) vs. displacement x graphs. Rank the graphs
according to the work done by F on the particle from x = 0 to x1, from the most
positive work to most negative work.
Rank here:_________________
6. Two clowns are launched from the same spring-loaded circus cannon with the spring
compressed the same distance each time. Clown A has a 40-kg mass; clown B a
60-kg mass. The relation between their kinetic energies at the instant of launch is
c.
3
KB.
2
3
KA 
KB .
2
KA  KB .
d.
KB 
e.
KB 
a.
b.
KA 
3
KA .
2
3
KA .
2
7. If the scalar (dot) product of two vectors is negative, it means that
a.
b.
c.
d.
e.
there was a calculator error.
the angle between the vectors is less than 90 degrees.
the angle between the vectors is 90 degrees.
the angle between the vectors is greater than 270 degrees.
the angle between the vectors is between 90 and 180 degrees.
-38.
A champion athlete can produce one horsepower (746 W) for a short period of
time. If a 70-kg athlete were to bicycle to the summit of a 500-m high mountain
while expending power at this rate, she would reach the summit in ____ seconds.
a.
b.
c.
d.
e.
1
460
500
1000
35 000
9. For a force to be a conservative force, when applied to a single test body
a.
b.
c.
d.
e.
10.
it must have the same value at all points in space.
it must have the same direction at all points in space.
it must be parallel to a displacement in any direction.
equal work must be done in equal displacements.
no work must be done for motion in closed paths.
A ball falls to the ground from height h and bounces to height h. Momentum is
conserved in the ball-earth system
a.
b.
c.
d.
e.
no matter what height h it reaches.
only if h < h.
only if h = h.
only if h > h.
only if h  h.
11. (Chapter 10) A disc, a sphere and a ring start rolling down an incline at the same
time. They all have the same mass and diameter. In what order will they reach the
bottom of the incline.
a.
All the same
b.
Disc, sphere, ring
c.
Disc, ring, sphere
d.
Sphere, ring, disc
e.
None of the above. My order is_________________________________
12. A cart of mass 1kg moving at 2 m/s along the positive x-axis rear-ends (collides)
with a cart of mass 3 kg moving along the positive x-axis with 1 m/s. The cars
stick together after the collision. Which statements are true and what is the
velocity of the carts after the collision?
a.
The collision is elastic.
b.
The collision is inelastic.
c.
Momentum and kinetic energy are conserved in this collision.
d.
The velocity of the carts after the collision is_______________
-4-
13. Can the center of mass of an object lie outside the contiguous part of the object?
If so, draw an object for which that is true.
a.
No
b.
Yes (Draw an example).
14.
Which of the following quantities are conserved in an inelastic collision?
a.
Kinetic energy
b.
Momentum
c.
Velocity
d.
Force
e.
Acceleration
15. (Chapter 10) A uniform sphere of radius R and mass M rotates freely about a
horizontal axis that is tangent to an equatorial plane of the sphere, as shown
below. The moment of inertia of the sphere about this axis is
a.
b.
c.
d.
e.
16.
2
MR
5
2
MR
3
5
MR
7
7
MR
5
3
MR
2
2
.
2
.
2
.
2
.
2
.
(Chapter 10) The angular speed of the minute hand of a clock, in rad/s, is
a.
b.
c.
d.
e.
1
.
1800
1
.
60
1
.
30
.
120.
-5-
Answers:
1b
2d
3c
4c
5 b-a-c-d
6c
7e
8b
9e
10a
11e
12b, d 1.25m/s
13b
14b
15d
16a