Download Physics MC Test thru 17 A runner moves along a circular track at a

Physics
MC Test thru 17
1. A runner moves along a circular track at a constant speed.
a.
b.
c.
d.
His acceleration is zero.
His velocity is constant.
Both (a) and (b) are true.
Both his acceleration and his velocity are changing.
2. Which car has a westward acceleration?
a.
b.
c.
d.
e.
a car traveling westward at constant speed
a car traveling eastward and speeding up
a car traveling westward and slowing down
a car traveling eastward and slowing down
a car starting from rest and moving toward the east
3. The equation for the speed of sound in a gas states that 𝑣 = √𝛾𝑘𝑏 𝑇/𝑚. Speed, v, is
measured in m/s, γ is a dimensionless constant, T is temperature in Kelvins (K), and
m is mass in kg. What are the units for the Boltzmann constant, 𝑘𝑏 ?
a. 𝑘𝑔 · 𝑚2 · 𝑠 2 · 𝐾
d. 𝑘𝑔 · 𝑚/𝑠
4.
b. 𝒌𝒈 · 𝒎𝟐 · 𝒔−𝟐 · 𝑲−𝟏
c. 𝑘𝑔−1 · 𝑚−2 · 𝑠 2 · 𝐾
e. 𝑘𝑔 · 𝑚2 · 𝑠 −2
A hunter spots a pheasant flying along horizontally. If he shoots the pheasant, the
time interval between the bird being shot and the dead bird hitting the ground
depends on
a. the speed with which the bird was flying.
b. the height of the bird above the ground.
c. the speed of the bird and its height above the ground.
5. A kicker kicks a football from the five yard line to the 45-yard line(both on the
same half of the field). Ignoring air resistance, where along the trajectory is the
speed of the football a minimum?
a.
b.
c.
d.
e.
at the 5-yard line, just after the football leaves the kicker’s foot
at the 45-yard line, just before the football hits the ground
at the 15-yard line, while the ball is still going higher
at the 35-yard line, while the ball is coming down
at the 25-yard line, when the ball is at the top of its trajectory
6. A person stands on the roof garden of a tall building with one ball in each hand.
If the red ball is thrown horizontally off the roof and the blue ball is
simultaneously dropped over the edge, which statement is true?
a. Both balls hit the ground at the same time, but the red ball has a
higher speed just before it strikes the ground.
b. The blue ball strikes the ground first, but with a lower speed than the red
ball.
c. The red ball strikes the ground first with a higher speed than the blue ball.
d. Both balls hit the ground at the same time with the same speed.
7. Two projectiles launched with the same initial speed but at different launch angles
30° and 60° land at the same spot. Ignore air resistance.
Which has the larger horizontal velocity component?
a. projectile launched at 30°
b. projectile launched at 60°
c. They are equal.
8. Interaction partners
a.
b.
c.
d.
e.
are equal in magnitude and opposite in direction and act on the same object.
are equal in magnitude and opposite in direction and act on different objects.
appear in an FBD for a given object.
always involve gravitational force as one partner.
act in the same direction on the same object.
9. Which of these is not a long-range force?
a.
b.
c.
d.
the force that makes raindrops fall to the ground
the force that makes a compass point north
the force that person exerts on a chair while sitting
the force that keeps the Moon in its orbital path around the Earth
10. A space probe leaves the solar system to explore interstellar space. Once it is far
from any stars, when must it fire its rocket engines?
a.
b.
c.
d.
e.
All the time, in order to keep moving.
Only when it wants to speed up.
When it wants to speed up or slow down.
Only when it wants to turn.
When it wants to speed up, slow down, or turn.
11. A boy swings in a tire swing. When is the tension in the rope the greatest?
a.
b.
c.
d.
at the highest point of the motion
at the lowest point of the motion
at a point neither highest nor lowest
it is constant
12. An astronaut is out in space far from any large bodies. He uses his jets to start spinning,
then releases a baseball he has been holding in his hand. Ignoring the gravitational force
between the astronaut and the baseball, how would you describe the path of the baseball
after it leaves the astronaut’s hand?
a. It continues to circle the astronaut in a circle with the same radius it had before
leaving the astronaut’s hand.
b. It moves off in a straight line.
c. It moves of in an ever-widening arc.
13. Two balls are thrown from the roof of a building with the same initial speed. One is
thrown
horizontally while the other is thrown at an angle of 20 degrees above the horizontal.
Which hits the ground with the greatest speed? Ignore air resistance.
a.
b.
c.
d.
The one thrown at 20 degrees.
The one thrown horizontally.
They hit the ground with the same speed.
The answer cannot be determined with the given information.
14. Two particles A and B of equal mass are located at some distance from each other.
Particle A is at rest while B moves away from A at speed v. What happens to the center
of mass of the system of two particles?
a.
b.
c.
d.
e.
It does not move.
It moves with a speed 1/2v away from A.
It moves with a speed v away from A.
It moves with a speed of v toward A.
It moves with a speed 1/2v toward A.
15. When both are expressed in terms of SI base units, torque has the same unit as
a. angular acceleration
b. angular momentum
c. force
d.energy
e. rotational inertia
ab. angular velocity
16. The SI units of angular momentum are
𝑟𝑎𝑑
a.
𝑠
𝑘𝑔 . 𝑚2
d.
𝑠2
b.
e.
𝑟𝑎𝑑
𝑠2
𝒌𝒈 . 𝒎𝟐
𝒔
c.
𝑘𝑔 . 𝑚
ab.
𝑠2
𝑘𝑔 . 𝑚
𝑠
17. Bernoulli’s equation applies to
a.
b.
c.
d.
e.
any fluid.
an incompressible fluid, whether viscous or not.
an incompressible, nonviscous fluid, whether the flow is turbulent or not.
an incompressible, nonviscous, nonturbulent fluid.
a static fluid only.
18. Two spheres, A and B, fall through the same viscous fluid.
A and B have the same density; A has the larger radius. Which has the larger terminal
velocity?
a. A
b. B
c. They are the same.
d. Not enough info to solve.
19. The continuity equation is an expression of
a.
b.
c.
d.
conservation of mass.
conservation of energy.
conservation of momentum.
conservation of angular momentum.
20. A body is suspended vertically from an ideal spring. The spring is initially in its relaxed
position. The body is then released and oscillates about the equilibrium position.
The acceleration of the body is zero when:
a.
b.
c.
d.
The spring is relaxed.
The body is at the equilibrium point.
The spring is at its maximum extension.
The spring is somewhere between the equilibrium point and the maximum extension.
21. A stiff material is characterized by
a.
b.
c.
d.
high ultimate strength.
high breaking strength.
high Young’s modulus.
high proportional limit.
22. Among these choices, which is/are correct units for electric field?
a. N/kg only
b. N/C only
c. N only
d. (N)(m/C) only
e. V/m only
ab. both N/C and V/m
23. Two solid metal spheres of different radii are apart. The spheres are connected by a fine
metal wire. Some charge is placed on one of the spheres. After electrostatic equilibrium
is reached, the wire is removed. Which of these quantities will be the same for the two
spheres?
a. the charge on each sphere
b. the electric field inside of each sphere, at the same distance from the center of the
spheres
c. the electric field just outisde the surface of each sphere
d. the electric potential at the surface of each sphere
e. both (b) and (c)
ab. both (b) and (d)
ac. both (a) and (c)
24. An equation for potential energy states U = mgh. If U is in 𝑘𝑔 · 𝑚2 · 𝑠 −2 , what are the
units of h?
a. s
b. 𝑠 2
c. 𝑚−1
d. m
e. 𝑔−1
25. A ball is thrown straight up into the air. Ignore air resistance. While the ball is in tha air
its acceleration
a.
b.
c.
d.
e.
increases.
is zero.
remains constant.
decreases on the way up and increases on the way down.
changes direction.
26. A toy rocket is propelled straight upward from the ground and reaches a height Δy.
After an elapsed time Δt, measured from the time the rocket was first fired off, the rocket
has fallen back down to the ground, landing at the same spot from which it was launched.
What is the average speed of the rocket during this time?
a. zero
𝜟𝒚
b. 𝟐 𝜟𝒕
c.
𝛥𝑦
𝛥𝑡
d.
𝛥𝑦
2𝛥𝑡
27. A boy plans to cross a river in a rubber raft. The current flows from north to
south at 1 m/s. In what direction should he head to get across the river to the east
bank in the least amount of time if he is able to paddle the raft at 1.5 m/s in still
water?
a.
b.
c.
d.
directly to the east
south of east
north of east
The three directions require the same time to cross the river.
28. Two balls, identical except for color, are projected horizontally from the roof of a tall
building at the same instant. The initial speed of the red ball is twice the initial speed of
the blue ball. Ignoring air resistance,
a.
b.
c.
d.
the red ball reaches the ground first
the blue ball reaches the ground first
both balls land at the same instant with different speeds
both balls land at the same instant with the same speed
29. A ball is thrown into the air and follows a parabolic trajectory. At the highest point in the
trajectory,
a.
b.
c.
d.
the velocity is zero, but the acceleration is not zero.
both the velocity and the acceleration are zero.
the acceleration is zero, but the velocity is not zero.
neither the acceleration nor the velocity are zero.
30. A ball is thrown into the air and follows a parabolic trajectory. Point A is the highest
point in the trajectory and point B is a point as the ball is falling back to the ground.
Choose the correct relationship between the speeds and the magnitudes of the
acceleration at the two points.
a.
b.
c.
d.
𝑣𝐴 > 𝑣𝐵 and 𝑎𝐴 = 𝑎𝐵
𝑣𝐴 < 𝑣𝐵 and 𝑎𝐴 > 𝑎𝐵
𝑣𝐴 = 𝑣𝐵 and 𝑎𝐴 ≠ 𝑎𝐵
𝒗𝑨 < 𝒗𝑩 and 𝒂𝑨 = 𝒂𝑩
31. Two projectiles launched with the same initial speed but at different launch angles 30°
and 60° land at the same spot. Ignore air resistance.
Which has a longer time of flight?
a. projectile launched at 30°
b. projectile launched at 60°
c. They are equal.
32. Two projectiles launched with the same initial speed but at different launch angles 30°
and 60° land at the same spot. Ignore air resistance.
For which is the product 𝑣𝑥 𝛥𝑡 larger?
a. projectile launched at 30°
b. projectile launched at 60°
c. 𝐓𝐡𝐞𝐲 𝐚𝐫𝐞 𝐞𝐪𝐮𝐚𝐥.
33. Within a given system, the internal forces
a. are always balanced by the external forces.
b. all add to zero.
c. are determined only by subtracting the external forces from the net force on the
system.
d. determine the motion of the system.
e. can never add to zero.
34. A friction force is
a.
b.
c.
d.
e.
a contact force that acts parallel to the contact surfaces.
a contact force that acts perpendicular to the contact surfaces.
a scalar quantity since it can act in any direction along a surface.
always proportional to the weight of an object.
always equal to the normal force between the objects.
35. When a force is called a “normal” force, it is
a.
b.
c.
d.
e.
the usual force expected given the arrangement of a system.
a force that is perpendicular to the surface of the earth at any given location.
a force that is always vertical.
a contact force perpendicular to the contact surfaces between two solid objects.
the net force acting on a system.
36. Your car won’t start, so you are puching it. You apply a horizontal force of 300 N to the
car, but it doesn’t budge. What force is the interaction partner of the 300 N force you
exert?
a.
b.
c.
d.
e.
the frictional force exerted on the car by the road
the force exerted by the car on you
the frictional force exerted on you by the road
the normal force on you by the road
the normal force on the car by the road
37. When an object is in translational equilibrium, which of these statements is not true?
a.
b.
c.
d.
The vector sum of the forces acting on the object is zero.
The object must be stationary.
The object has a constant velocity.
The speed of the object is constant.
38. To make an object start moving on a surface with friction requires
a.
b.
c.
d.
less force than to keep it moving on the surface.
the same force as to keep it moving on the surface.
more force than to keep it moving on the surface.
a force equal to the weight of the object.
39. A small plane climbs with a constant velocity of 250 m/s at an angle of 28° with respect
to the horizontal. Which statement is true concerning the magnitude of the net force on
the plane?
a. It is equal to zero.
b. It is equal to the weight of the plane.
c. It is equal to the magnitude of the force of air resistance.
d. It is less than the weight of the plane but greater than zero.
e. It is equal to the component of the weight of the plane in the direction of motion.
40. A spider sits on a turntable that is rotating at a constant 33 rpm. The acceleration of the
spider is
a.
b.
c.
d.
greater the closer the spider is to the central axis.
zero.
greater the farther the spider is from teh central axis.
nonzero and independent of the location of the spider on the turntable.
41. A boy swings in a tire swing. When is the tangential acceleration the greatest?
a.
b.
c.
d.
at the highest point of the motion
at the lowest point of the motion
at a point neither highest nor lowest
it is constant
42. An object moving in a circle at a constant speed has an acceleration that is
a.
b.
c.
d.
in the direction of motion
zero
away from the center of the circle
toward the center of the circle
43. A hiker descends from the South Rim of the Grand Canyon to teh Colorado River.
During his hike, the work done by gravity on the hiker is
a.
b.
c.
d.
e.
positive and independent of the path taken
negative and depends on the path taken
positive and depends on the path taken
negative and independent of the path taken
zero
44. A glass of ice water if filled to the brim with water; the ice cubes stick up above the water
surface. After the ice melts, which is true?
a. The water level is below the top of the glass.
b. The water level is at the top of the glass but no water has spilled.
c. Some water has spilled over the sides of the glass.
d. Impossible to say without knowing the initial densities of the water and the ice.
45. A dam holding back the water in a reservoir exerts a horizontal force on the water. The
magnitude of this force depends on
a.
b.
c.
d.
e.
the maximum depth of the reservoir.
the depth of the water at the location of the dam.
the surface area of the reservoir.
both (a) and (b).
all of the above.
46. Two spheres, A and B, fall through the same viscous fluid.
A and B have the same radius; A has the larger mass. Which has the larger terminal
velocity?
b. A
b. B
c. They are the same.
d. Not enough info to solve.
47. Bernoulli’s equation is an expression of
a.
b.
c.
d.
conservation of mass.
conservation of energy.
conservation of momentum.
conservation of angular momentum.
48. Which of these units can be used to measure electric potential?
a.
b.
c.
d.
e.
N/C
J
(V)(m)
V/m
(N)(m)/C
49. A parallel plate capacitor is attached to a battery that supplies a constant potential
difference. While the battery is still attached, the parallel plates are separated a little
more. Which statement describes what happens?
a.
b.
c.
d.
The electric field increases and the charge on the plate decreases.
The electric field remains constant and the charge on the plate increases.
The electric field remains constant and the charge on the plate decreases.
Both the electric field and the charge on the plates decrease.
50. A tiny charged pellet of mass m is suspended at rest between two horizontal, charged
metallic plates. The lower plate has a positive charge and the upper plate has a negative
charge. Which statement in the answers here is not true?
a.
b.
c.
d.
The electric field betweent the plates points vertically upward.
The pellet is negatively charged.
The magnitude of the electric force on the pellet is equal to mg.
The plates are at different potentials.