Physics Midterm (Chp 1 to 8)
A right triangle has sides 10 m, 5 m, and 11 m (measured to nearest whole number). The smallest angle of this triangle is nearest to _____ degrees.
27
If both mass and velocity of a ball are tripled, its kinetic energy is increased by a factor of _____.
27
Calculate (0.83 + 0.049)(4.4 × 103 ), keeping only significant figures.
3,900
Two wires support a post, with dimensions as shown in the figure. If d = 14 m, what is the value of x?
5.2 m
On planet Z, the standard unit of length is the foose. Ann the Astronaut is 5.2 feet tall on Earth. She lands on planet A and is measured to be 88 foosi tall. Her partner Rachael is 92 foosi tall. How tall is Rachael on Earth?
5.4 ft
A cement truck can pour 160 cubic yards of cement per hour. Express this in ft3 /min. (Hint: You do NOT need SI units for this problem!)
72.0 ft3/min
A taxicab moves five blocks due north, five blocks due east, and another three blocks due north. Assume all blocks are of equal size. How far is the taxi from its starting point?
9.4 blocks
The law of conservation of linear momentum is applicable to systems made up of objects described by which of the following?
All of these choices are valid.
The net force on an object is in the positive x-direction. Consider the following statement.
I) The object can be moving in the negative x-direction. II) The object can be speeding up. III) The object can be slowing down. IV) The object can be moving in the positive y-direction.
In a problem using energy considerations to solve for the speed of a ball thrown from the top of a building when it strikes the ground below, where should the potential energy have is zero value?
It doesn't matter since only differences in potential energy matter in solutions
Object 1 has twice the mass of Object 2. Both objects have the same kinetic energy. Which of the following statements is true?
Object 1 has momentum of greater magnitude than Object 2.
What forces are included in a free-body diagram for an object?
Only the forces acting on the object.
A rock is moving with speed V. If the mass of the rock were tripled and the speed were reduced to V/3, which of the following statements would be true?
The kinetic energy of the rock is smaller than in the first case, but the momentum is the same.
In an automobile collision, how does an airbag lessen the blow to the passenger? Assume as a result of the collision, the passenger stops.
The stopping impulse is the same for either the hard objects or the airbag. Unlike the windshield or dashboard, the air bag increases the time for the slowing process and thus decreases the average force on the passenger.
A baseball is thrown by the center fielder (from shoulder level) to home plate, where it is caught (on the fly at shoulder level) by the catcher. At what point is the magnitude of the acceleration at a minimum? (Air resistance is negligible.)
acceleration is constant during the entire trajectory
When we add a displacement vector to another displacement vector, the result is __________ .
another displacement
Which formula is dimensionally consistent with an expression yielding a value for velocity? (a is acceleration, x is distance, and t is time.)
at
Jeff throws a ball straight up. For which situation is the vertical velocity zero?
at the top
A baseball is thrown by the center fielder (from shoulder level) to home plate, where it is caught (on the fly at an equal shoulder level) by the catcher. At what point is the ball's speed at a minimum? (Air resistance is negligible.)
at the top of the trajectory
A baseball is thrown by the center fielder (from shoulder level) to home plate, where it is caught (on the fly at shoulder level) by the catcher. At what point does the magnitude of the vertical component of velocity have its minimum value? (Air resistance is negligible.)
at the top of the trajectory
If we know that a nonzero net force is acting on an object, which of the following must we assume regarding the object's condition? The object is __________.
being accelerated
Two objects of different mass are released simultaneously from the top of a 20-m tower and fall to the ground. If air resistance is negligible, which statement best applies?
both objects hit the ground together
Two projectiles are launched at 100 m/s, the angle of elevation for the first being 30 degrees and for the second being 60 degrees. Which of the following statements is FALSE?
both projectiles have the same range
Any object moving in a circular path has an acceleration directed toward the center of the circle. This is called __________ acceleration.
centripetal
A billiard ball collides in an elastic head-on collision with a second stationary identical ball. After the collision, which of the following conditions applies to the first ball?
comes to rest
In a two-dimensional Cartesian coordinate system, the x-component is equal to that vector's magnitude multiplied by which trigonometric function, with respect to the angle between the vector and the x-axis?
cosine
Which of the following is an example of a nonconservative force?
friction
Which of the following is an example of the type of force that acts at a distance?
gravitational, magnetic, electrical
The maximum possible value for the coefficient of static friction is __________.
greater than 1.00
As a basketball player starts to jump for a rebound, he begins to move upward faster and faster until he leaves the floor. During this time that he is in contact with the floor, the force of the floor on his shoes is _________.
greater than his weight
A Hooke's Law spring is compressed a distance d and is used to launch a mass m vertically to a height h above its starting position. Under the same compression d, the spring is now used to launch a mass of 2m. How high does the second mass rise?
h/2
In the case of constant acceleration, the average velocity equals the instantaneous velocity __________.
halfway through the time travel
. What condition must apply to a system's state of motion for it to be regarded as an inertial frame of reference?
in constant velocity
A projectile is launched at an angle less than 30 degrees and at speed V. Which of the following will increase the projectile's range the most, ignoring air resistance?
increasing the launch speed by 50%
A block is launched up an incline plane. After going up the plane, it slides back down to its starting position. The coefficient of friction between the block and the plane is 0.3. The speed of the bock when it reaches the starting position on the trip down
is less than the launching speed
A block is launched up an incline plane. After going up the plane, it slides back down to its starting position. The coefficient of friction between the block and the plane is 0.3. The time for the trip up the plane is __________.
is less than the time for the trip down
When a Hooke's Law spring is stretched a distance of 3x, how much is the increase in energy stored in it from when it was stretched a distance x? Give your answer in terms of a multiple of the energy stored in the spring when it is stretched a distance x.
it is 9 times as much
A car is going around a racetrack at constant speed. The curves around the track have different radii. In which turn does the car experience the greatest centripetal acceleration?
it is greatest in the turn with the smallest radius
In one-dimensional motion, the average speed of an object that moves from one place to another and then back to its original place has which of the following properties?
it is postive
An object is dropped from a height. Once it is moving, which of the following statements is true, at least at one point?
its velocity is never equal to its acceleration
The unit of power - the watt - is dimensionally the same as __________.
joule/second
Two masses M1 and M2, with M1 < M2, have momenta with equal magnitudes. How do their kinetic energies compare?
ke1>ke2
The units of impulse are equivalent to __________.
kg m/s
Which of the following is a valid unit for momentum?
kg m/s
The SI units for the spring constant k are equivalent to __________.
kg/s2
Which of the following is the form of energy associated with an object's motion?
kinectic
Areas always have dimensions of _____ while volumes always have dimensions _____.
l2,l3
In mechanics, physicists use three basic quantities to derive additional quantities. Mass is one of the three quantities. What are the other two?
length and time
The speed of a boat I soften given in knots. If a speed of 5 knots were expressed in the SI system of unites, the units would be __________.
m/s
What are the correct units for tangential velocity?
m/s
Jasper takes two books of mass M1 and M2 off the floor and places them on a shelf at height H. The change in potential energy of the book with mass M1 is four times that of the book with mass M2. What is the relationship between M1 and M2?
m1=4m2
Which of the following is NOT a vector quantity?
mass
The impulse experienced by a body is equivalent to its change in __________.
momentum
A box slides across a floor and comes to rest. The work done by the frictional force on the box is __________.
negative
The unit of work - the joule - is dimensionally the same as __________.
newton-meter
If the momentum of an object is tripled, its kinetic energy will change by what factor?
nine times
A hiker walks 200 m west and then walks 100 m north. In what direction is her resulting displacement?
none of these answers
Consider a point on a bicycle wheel as the wheel turns about a fixed axis, neither speeding up nor slowing down. Compare the linear and angular accelerations of the point.
only the angular acceleration zero
Consider a point on a bicycle wheel as the wheel turns about a fixed axis, neither speeding up nor slowing down. Compare the linear and angular velocities of the point.
only the angular velocity is constant
Consider a point on a bicycle wheel as the wheel makes exactly four complete revolutions about a fixed axis. Compare the linear and angular displacements of the point.
only the linear displacement is zero
The work done by static friction can be __________.
positive, negative, zero
Which of the following is the form of energy associated with an object's location in a conservative force field?
potential
Which of the following is not true about potential energy?
potential energy has direction
The rate at which work is done is equivalent to which of the following?
power
What are the correct units for angular velocity?
rad/s
What are the correct units for angular acceleration?
rad/s2
The value of an object's acceleration may be characterized in equivalent words by which of the following?
rate of change of velocity
In a two-dimensional Cartesian coordinate system, the y-component is equal to that vector's magnitude multiplied by which trigonometric function, with respect to the angle between the vector and the x-axis?
sine
Changing the positive direction in a reference frame to the opposite direction does not change the sign of which of the following quantities?
speed
Which of the following is not a vector quantity?
temperature
. A strobe photograph of a car moving along a straight road shows the interval between each successive image to be diminishing. If the direction of motion of the car is taken as positive, which of the following is/are negative?
the average acceleration of a car
A lump of clay is thrown at a wall. A rubber ball of identical mass is thrown with the same speed toward the wall. Which statement is true? [Which object will bounce? What does this mean about the change in momentum?]
the ball experience a greater change in momentum than the clay
Two blocks are released form the top of a building. One falls straight down, while the other one slides down a smooth ramp. If all friction is ignored, which one is moving faster when it reaches the bottom?
the both will have the same speed
A projectile is launched at an angle (theta) above the horizontal. Three seconds later the projectile is moving at the same angle (theta) below the horizontal. Which of the following (actual values with units, not just algebraic symbols) can be found from the information given?
the initial vertical component of the projectile's velocity
Which of the following expresses a principle, which was initially stated by Galileo and was later incorporated in Newton's laws of motion?
the natural condition for a moving object is to remain in motion
. If we know an object is moving at constant velocity, we may assume __________.
the net force acting on the object is zero
As a car goes up a hill, there is a force of friction between the road and the tires rolling on the road. The maximum force of friction is equal to __________.
the normal force of the road times the coefficient of static friction
What are the correct units for the radian?
the radian is unitless ration
A billiard ball collides in an elastic head-on collision with a second identical ball. The kinetic energy of the system after the collision is __________ the kinetic energy of the system before the collision.
the same as
If a glass of water is on a table with a piece of paper under it, it is relatively easy to pull the paper out without disturbing the glass very much of the pull is done very quickly. This is because, with a quick pull, __________.
the time for the pull will be less
A moderate force will break an egg. However, an egg dropped on the road usually breaks, but one dropped on the grass usually doesn't break. This is because __________ for the egg dropped on the grass.
the time interval for stopping is greater
Starting from rest, a wheel undergoes constant angular acceleration for a period of time T. At what time after the start of rotation does the wheel reach an angular speed equal to its average angular speed for this interval?
0.50 T
The highest mountain on Mars is Olympus Mons, rising 22,000 meters above the Martian surface. If we were to throw an object horizontally of the mountain top, how long would it take to reach the surface? (On Mars, g = 3.72 m/s2 . Ignore air resistance.)
1.8 minutes
. Which one of the choices below represents the preferred practice regarding significant figures when adding the following: 15.9 + 14 + 77.68 + 6.898?
114
An object moves at a constant velocity of 12 m/s to the southwest for an interval of 20 s. Halfway through this interval, what is the magnitude of its instantaneous velocity?
12 m/s
An object moves at a constant velocity of 12 m/s to the southwest for an interval of 20 s. Halfway through this interval, what is the magnitude of its instantaneous velocity?
12 m/s
Which one of the choices below represents the preferred practice regarding significant figures when multiplying the following: 15.0 × 5.6 × 2.33?
200
A physics student is riding on a train traveling north. Having read about inertia, the student performs an experiment with a golf ball. He reaches over the aisle and drops the ball from rest. Instead of hitting the floor directly below the student's, it hits to the north, i.e. forward of that position (in the direction the train is traveling). Which of the following might be the cause for this to happen?
the train is slowing down
The statement by Newton that "for every action there is an opposite but equal reaction" is regarded as which of his laws of motion?
third
I like it when a question is easy, and I can get 7 points for clicking on "True."
true
The equations of angular motion are the same as the equations for linear motion, with only a change in variables.
true
The kinetic energy of an object is quadrupled. Its momentum will change by what factor?
two times
If a is acceleration, v is velocity, x is position, and t is time, then which equation is not dimensionally correct?
v= a/t
Displacement is which of the following types of quantities?
vector
Which type of quantity is characterized by both magnitude and direction?
vector
Which of the following is an example of a vector quantity?
velocity
In the terminology a 500-N block, the 500-N refers to the block's __________.
weight
A change in a physical quantity w having initial value wi and final value wf is given by which of the following?
wf-wi
Two baseballs are released at the same time. One is dropped from rest and the other is given an initial horizontal velocity. Which of the following is NOT true? (Ignore atmospheric drag.)
The horizontal component of velocity increases at a greater rate than the vertical component of velocity for both while they are both in the air.
Which formula is dimensionally consistent with an expression yielding a value for velocity? (a is acceleration, x is distance, and t is time)
a t