2017-18 MULTIPLE CHOICE Final Physics Exam
Speed is ___.
(1) a measure of how fast something is moving. (2) always measured in terms of a unit of length divided by a unit of time. (3) a scalar quantity.
The law of inertia states that
(1) an object will continue moving at the same velocity unless a net force acts on it. (2) an object will continue moving in a straight line unless a net force acts on it. (3) an object that is not moving will never move unless a net force acts on it. (4) an object at rest will remain at rest unless acted on by a net force.
According to Newton, the gravitational force between two massive objects
(1) is always an "attraction" force. (2) depends on how massive they are. (3) depends inversely on the square of the distances between them.
Which of the following items are considered to be the conundrums that all early models of the universe sought to solve? (Choose all that apply.)
(1) the varying speeds of planets (2) retrograde motion (3) parallax
As a pendulum swings back and forth:
- at the endpoints of its swing, its energy is all potential - at the lowest part of its swing, its energy is all kinetic. - kinetic energy is transformed into potential energy. - potential energy is transformed into kinetic energy.
A ball is thrown straight up. At the top of its path its instantaneous speed is
0 m/s
The orbital period of earth is
1 year
A car accelerates at 2 m/s/s. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 20 m/s?
10 seconds Vf = Vi + at 20 m/s = 0 + 2 m/s/s x time 10 seconds = time
Which is larger: 100 yards or 100 meters?
100 meters.
The mass of a dog that weighs 110N is about ....
11kg F=ma M=f/a M=110/9.8
A 4.0 kg block is pulled along a frictionless table with a force of 8.0 N as shown below. The acceleration of the box is..
2m/s/s F = ma 8.0=4.0a a=2 m/s/s
A 15-N force and a 45-N force act on an object in opposite directions. What is the magnitude of the NET FORCE acting on the object?
30N
Suppose a jumper claims a hang time of 2 seconds. Then that jumper must be able to jump a vertical distance of about
5 meters
A stealth ninja begins her travels at a large tree. She travels 5 m east, then 10 meters west. The ninja's total displacement is
5 meters west
A group of science students attempt to determine the mass of steel ball. Each student measures the ball on a different balance in the science lab. They record the following measurements: 50.7 g, 49.37 g, 49.67 g and 50.2 g. As a result, the students correctly report the mass of the ball as
50.0 g
The mean distance between planet X and the sun is 15 AU. What is the orbital period for planet X?
58 years. t^2 = a^3 ; solve for t.
A train travels 6 meters in the first second of travel on a straight track, 6 meters again during the second second of travel, and 6 meters again during the third second. Its acceleration is
6 m/s/s
How much WORK is done lifting a 200 N cow 3 meters straight up?
600J W = FdcosO W = (200)(3)(cos0) W = 600J
A husband and wife decide to divide and conquer their errands. The husband travels a total distance of 10 km and is out for 2 hours. The wife travels a total distance of 7 km and is out for 1.5 hours. If they both began at home, who has the greater displacement once they both are back home?
Both are the same.
Give an example of a non-vector.
Distance.
T or F: In physics, the amount of work done on an object is the product of the force exerted on the object and the amount of time the object is in motion.
False
The only forces acting on an object in FREE FALL are gravity and air resistance.
False
An object with no net force acting on it must be at rest.
False.
In order to make a cart move forward, a horse must pull harder on the cart than the cart pulls on the horse.
False.
T or F: 1kg = 1000m
False.
T or F: Mass is a vector quantity.
False.
T or F: Simple machines are useful because they decrease the amount of work needed to get the job done.
False.
T or F: The acceleration due to gravity on at object at sea level is the same as the acceleration due to gravity on the same object at the top of Mount Everest.
False.
T or F: The force due to gravity acting on an object is its mass.
False.
Two teams in a tug of war exert the same amount of force and the rope does not move. Which one of Newton's Laws explains why the rope does not move?
First Law
You are floating over one of those massive fans which give you the experience of sky diving. If you float in the same place. How is the fan effecting your your movement?
Force equal in magnitude and opposite in direction to gravity.
Consider the kinematic graph shown below. The scientific question this graph answers is (stopping distance on y-axis and speed on x-axis)
How does speed affect stopping distance?
If the radius of the Earth decreased, with no change in its mass, your weight would:
Increase
The fact that the paths of the planets are ellipses with the center of the sun at one focus is explained by
Kepler's First Law of Planetary Motion
According to ___________, an imaginary line from the sun to a planet sweeps out equal areas in equal time intervals
Kepler's Second Law
According to ___________, planets will travel at a faster orbital speed at perihelion than at aphelion.
Kepler's Second Law
Consider the elliptical orbit of a planet shown below. The area of each shaded triangle is equal to the others. Given this information regarding equal areas, which one of Kepler's Laws of Planetary Motion does this exemplify?
Kepler's Second Law
The impulse-momentum theorem is derived mathematically from
Newton's Third Law of Motion.
How much POWER does it take to lift an 800 N flat screen 1 meter in 2 seconds?
P = 400W Power = Work/Time P = Force x d x cosO/time P = 800(1)/2 P = 400W
Three toy cars race on a straight track and their motion is described on the position vs. time graph below. Which of the cars is accelerating?
The car that does not have a constant slope, so Car C.
A block slides down a rough ramp. Which of the following statements is true for the block-ramp system?
The kinetic energy of the block at the bottom of the ramp will be less than its potential energy at the top of the ramp.
Which has more momentum, a large truck traveling at 30 miles per hour or a small truck moving at 30 miles per hour?
The large truck.
An unfortunate bug splatters against the windshield of a moving car. Compared to the force of the car on the bug, the force of the bug on the car is
The same
A dart thrower, aiming at the bull's eye, hits the outside edge of the "20 wedge" three times. What is true?
The thrower is precise, but not accurate.
Pine tar (a sticky substance) is not allowed on the barrel of a baseball bat. Assuming that the mass and force with which the bat is swung stay the same, why would this be?
The time of impact increases, thus, the ball has a greater change in velocity and a greater exit velocity.
Hitting the bull's eye on a dart board repeatedly is an example of precision and accuracy...if the bull's eye is what you're aiming for, of course.
True
Science is a method of answering theoretical questions whereas technology is a method of solving practical problems.
True
T or F: 1 AU represents the average distance between the Earth and the sun for one orbital period.
True
T or F: Accuracy is the extent to which the measured and accepted values of a quantity agree.
True
T or F: Newton's First Law describes an object who's change in momentum is zero.
True
T or F: The direction of the net force acting on an object will point in the same direction as its acceleration.
True
T or F: The energy an object has due to its location or position is its potential energy.
True
T or F: When we carry an object across a room, without lifting it or setting it down, we do no physical work on it.
True
T or F: Airbags are used in automobiles to increase the stopping time for the occupants in case of a collision.
True.
T or F: Even though a car is slowing down, it is still accelerating, in the according to the physics definition of acceleration.
True.
T or F: The length of a vector arrow represents its magnitude.
True.
When you look at the speedometer in a moving car, you can see the car's
When you look at the speedometer in a moving car, you can see the car's
If a horse pulls on a wagon at rest, the wagon pulls back equally as much on the horse. Will the wagon be set into motion?
Yes, because the horse's pull on the wagon is larger than the wagon's pull on the horse.
Suppose you are in a car that is going around a curve. The speedometer reads a constant 30 miles per hour. What is NOT true?
Your velocity is constant.
Suppose an object is in free fall. Each second the object falls
a larger distance than in the second before.
Two billiard balls undergo a collision. Ball A has twice the mass and twice the speed as Ball B. During the collision, ball A encounters _________ acceleration.
a smaller
If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by
about 10 m/s
A ball is thrown straight up. At the top of its path the magnitude of its acceleration is
about 10 m/s/s.
An object's mass is constant. A net force acting on the object over time will produce a constant
acceleration
In the absence of air resistance, objects fall at constant
acceleration
A black hole is an object that
alters the space around it. has an enormous density. has an enormous gravitational field near it. has an escape speed greater than the speed of light. All of the above.
One difference between a hypothesis and a theory is that a hypothesis is
an educated prediction whereas as theory has been tested successfully many times.
A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always...
directed downward.
A rock is thrown vertically in the air. At the very top of its flight the net force on it is:
equal to the rock's weight
If you whirl a tin can on the end of a string and the string suddenly breaks, the can will
fly off, tangent to its circular path.
What is an example of NOT a fundamental unit in physics?
gram
With elliptical orbits, the location closest to the sun is where the planet has its ____.
greatest speed.
Light is different from objects with mass in that no matter how fast the source of light is moving, light always
has the same speed.
Give an example of a problem that would NOT be a part of physics.
identifying all the bones in a human body
When a car's speed triples, its kinetic energy
increases by a factor of 9
One object has twice as much mass as another object. The first object also has twice as much
inertia.
When a basketball player jumps to make a shot, once the feet are off the floor, the jumper's acceleration
is "g"; no more, no less.
If the momentum of an object changes and its mass remains constant then . .
it is accelerating (or decelerating). there is a net force acting on it. its velocity is changing.
Eccentricity is closest to 1 when...
it is squashed thinnest.
What remains constant for a satellite in an elliptical orbit?
its total energy
A box is accelerated across a table in a straight-line path with a constant force of 13 N. The friction force between the box and the table is
less than 13 N
The relationship between net force acting on an object and the object's acceleration is ...
linear.
A scalar is a quantity that has . . .
magnitude
An object that has kinetic energy must have . . .
momentum
Two objects, A and B, have the same size and shape, but A is twice as heavy as B. When they are dropped simultaneously from a tower, they reach the ground at the same time, but A has a higher
momentum
A track star runs the 400m event on the PC track. If the PC track is 400 m around, the track runner's position when crossing the finish line is: (make NO assumptions!)
not enough information is given
There are two main processes going on in the sun that keep the sun in existence. These processes are gravitation and ____.
nuclear fusion
Friction is a force that always acts
opposite to an object's motion.
The speed of a satellite in an elliptical orbit about the Earth is greatest at . . .
perigee
The point located at the shortest distance between one focus point and the elliptical orbit is called the . . .
perihelion
When applied to forces, the term "normal" means
perpendicular to the contact surface.
The degree of exactness to which the measurement of a quantity can be reproduced is called
precision
The average orbital radius of a planet in an elliptical orbit is equal to the
semi-major axis.
The force of gravity acting on you will increase if you ___.
stand on a planet with a radius that is shrinking.
The planet with the smallest eccentricity is the one
that is most circular.
Two physics students with the same mass bound up the same set of stairs. Which student will be the most POWERFUL?
the one that gets to the top the fastest.
Compared to its mass on Earth, the mass of a 10-kg object on the moon is
the same
Two billiard balls undergo a collision. Ball A has twice the mass and twice the speed as Ball B. During the collision, ball A encounters _________ force.
the same
A ball is thrown straight upwards and caught when it comes back down. In the absence of air resistance, the speed of the ball when caught would be . . .
the same as the speed it had when thrown upwards.
Two billiard balls undergo a collision. Ball A has twice the mass and twice the speed as Ball B. During the collision, ball A encounters _____ impulse.
the same.
Momentum of a system is conserved only when
there are no forces acting on the system.
A heavy object and a light object are released from rest at the same height and time. If air resistance can be ignored, then the objects have equal ___________ as they fall.
velocity
Acceleration is defined as the CHANGE in
velocity divided by the time interval
An object following a straight-line path at constant speed has ____
zero acceleration
After a cannonball is fired into frictionless space, the amount of force needed to keep it going equals
zero, since no force is necessary to keep it moving.
