Physics exam 1 CH 1-4 study guide
Amanda is standing at the edge of a cliff. She throws a rock vertically upward at speed v0, while at the same time throws a second rock vertically downward at the same speed. How long after the rock thrown downward hits the ground does the rock thrown upwards hit?
2v0/g
Doubling the radius of a sphere results in increasing its volume by a factor of
8
A projectile is launched with speed v at an angle θ, the angle being less than 45º. What other angle would give the same range for this projectile launched at the same speed v?
90° - θ
A projectile is fired at an angle of elevation of 30°. Neglecting air resistance, what are possible angles in flight between the acceleration vector and the velocity vector?
90° and 30°
It is late and Carlos is sliding down a rope from his third-floor window to meet his friend Juan. As he slides down the rope faster and faster, he becomes frightened and grabs harder on the rope, increasing the tension in the rope. As soon as the upward tension in the rope becomes equal to his weight:
Carlos will continue down at a constant velocity.
In one-dimensional motion where the direction is indicated by a plus or minus sign, the average velocity of an object has which of the following properties?
It can be positive, negative, or zero
Of vectors with lengths 5 m, 3 m, and 4 m, which has the greatest magnitude x component?
It could be any of the three
Suppose an equation relating position, x, to time, t, is given by x = bt^3 + ct^4, where b and c are constants. The dimensions of b and c are respectively:
L/T^3, L/T^4
Areas always have dimensions ____ while volumes always have dimensions ____
L^2, L^3
What forces are included in a free-body diagram for an object?
Only the forces acting on the object
How long has it been that scientists have accepted that the nucleus of the atom consists of neutrons and protons? Think of your answers in terms of order of magnitude.
about a century
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 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 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.
Since 1967 the standard definition for the second has been based on which of the following?
characteristic frequency of the cesium-133 atom
Volume can be measured in units of m^3. Which of the following unit combinations also result in volume?
cm^2in
Which is smallest, an atom, a nucleus, a proton, or an electron?
electron
Which is the correct expression for the force of static friction, where n is the normal force?
fs ≤ μsn
Which of the following is an example of the type of force that acts at a distance?
gravitational magnetic electrical (All of the above) * answer
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
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
A box of mass m is placed on an incline with angle of inclination θ. The box does not slide. The magnitude of the frictional force in this case is:
mg sin θ
A baseball is moving in the air along the customary parabola. Ignoring air drag, where is the force on the baseball zero?
nowhere
The value of an object's acceleration may be characterized in equivalent words by which of the following?
rate of change of velocity
Vector is 2 m long, and vector is 5 m long. The length of the sum of the vectors must be
some value from 3 m to 7 m
Vector A points north, and vector B points east. If C= B−A, then vector C points
south of east
A strobe photograph shows equally-spaced images of a car moving along a straight road. If the time intervals between images is constant, which of the following cannot be positive?
the acceleration of the car
A thrown stone hits a window, but doesn't break it. Instead it reverses direction and ends up on the ground below the window. In this case, we know:
the force of the stone on the glass = the force of the glass on the stone.
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.
The prefixes which are abbreviated f, d, and T represent which of the following?
10^-15, 10^-1, and 10^12
The ratio T/m of the prefixes M and m has what value?
10^15
Multiplying a 2-significant-figure number by a 4-significant-figure number and then dividing the product by a seven-significant-figure number yields a number with how many significant figures?
2
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 hand, it hits to the north, i.e., forward of that position. Which of the following might be the cause for this to happen?
the train is slowing down
A v vs. t graph is drawn for a ball moving in one direction. The graph starts at the origin and at t = 5 s the acceleration of the ball is zero. We know that at t = 5 s,
the velocity of the ball is not changing.
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
Which expression is dimensionally consistent with an expression that would yield a value for time−1? (v is velocity, x is distance, and t is time)
v/x
A change in a physical quantity w having initial value wi and final value wf is given by which of the following?
wf − wi
A baseball thrown from the outfield is released from shoulder height at an initial velocity of 28.3 m/s at an initial angle of 30.0° with respect to the horizontal. If it is in its trajectory for a total of 4.00 s before being caught by the third baseman at an equal shoulder-height level, what is the ball's net vertical displacement during its 4.00-s trajectory?
zero
As a car moves forward on a level road at constant velocity, the net force acting on the tires is:
zero
On a velocity-time graph for a particle, suppose the plot starts at some positive velocity and then follows a straight line to zero at a later time. Which of the following must be true about a position vs. time graph for this same time interval?
The curve will rise steeply at first and as time goes on will level out approaching its highest position value at the later time.
When SI units are plugged into an equation, it is found that the units balance. Which of the following can we expect to be true for this equation?
The equation will be dimensionally correct
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.