Physics Final
When representing velocity as a vector
-the direction of the arrow shows the direction of motion -the length of the arrow represents the speed -the length of the arrow is drawn to a suitable scale
Suppose you take a trip that covers 240 km and takes 4 hours to make. Your average speed is
0 km/h
A ball is thrown straight up. At the top of its path its instantaneous speed is
0 m/s
An object travels 8 meters in the first second of travel, 8 meters again during the next second of travel, and 8 meters again during the third second second. Its acceleration is
0 m/s squared
A cannonball is launched horizontally from a tower. If the cannonball has a barrel velocity of 100 m/s, where will the cannonball be 1 second later? (Neglect air resistance).
100 m downrange
In the absense of air resistance, the angle at which a thrown ball will go the furthest is
45 degrees
A ball is hurled into the air at an angle of 30 degrees above the horizontal and lands on a target that is at the same level as that where the ball started. The ball will also land on the target if it is thrown at an angle of
60 degrees
The scientific study of sound, especially of its generation, transmission, and reception
Acoustics
Suppose a particle is accelerated through space by a constant 10-N force. Suddenly the particle encounters a second force of 10-N in a direction opposite to that of the first force. The particle
continues at the speed it has when it encountered the second force
The same unfortunate bug splatters against the windshield of a moving car. Compared to the acceleration (deceleration) of the car, the deceleration of the bug is
larger
A vector is a quantity that has
magnitude and direction
The momentum of an object is defined as the object's
mass times its velocity
A moving freight car runs into an identical car at rest on the track. The cars couple together. Compared to the velocity of the first car before the collision, the velocity of the combined cars after the collision is
only half as large
Potential energy is the energy an object has because of its
position or configuration
If no external work is done by nonconservative forces, the total mechanical energy of a system
remains constant
When in orbit, a satellite such as the space shuttle is
simply a projectile
Nellie Newton holds an apple in her hand. If action is Earth pulling on the apple, then reaction is
the apple pulling on the earth
A Ping-Pong ball launcher is fired. Compared to the force on the ball, the force on the launcher is
the same
A Ping-Pong ball launcher is fired. Compared to the impulse on the ball, the impulse on the launcher is
the same
If an object has kinetic energy, then its potential energy is 0 J.
False
State Newton's 3rd law of motion
For every action force there is an equal and opposite reaction force
Grandma H challenges Michael Johnson in the 400-meter dash. Grandma H spins her wheelchair wheels five times and gives up after traveling 15 from the starting line. MJ makes a complete circle around the track and stops at the starting line. In this race,
Grandma Henderson has the greatest displacement
If you drop a feather and a coin at the same time in a tube filled with air, which will reach the bottom of the tube first? Consider air resistance
The coin
An object moving at a constant velocity MUST
be experiencing a balance of forces
The law of inertia applies to
both moving and nonmoving objects
If an object has an acceleration then it MUST be
changing its velocity
A moving freight car runs into a identical car at rest on the track. The cars couple together. Compared to the momentum of the first car before the collision, the momentum of the combined cars after the collision is
the same
The poor bug splatters against the dirty windshield of a moving car. Compared to the impulse on the car, the impulse on the bug is
the same
The tortured bug splatters against the windshield of a moving car. Compared to the change in momentum of the car, the change in momentum of the bug is
the same
After a rock that is thrown straight up reaches the top of its path and is starting to fall back down, its acceleration is (neglecting air resistance)
the same as when it was at the top of its path
If Kelly the skater's speed increases so he has twice the momentum, then his KE increases by
four times
How much farther will a car traveling at 100 km/s skid than the same car traveling at 50 km/s?
four times as far
The momentum change of an object is equal to the
impulse acting on it
If the momentum of an object changes and its mass remains constant
its velocity is changing it is accelerating (or decelerating) there is a net force acting on it
A ball is thrown straight up. At the top of its path its acceleration is
-10 m/s sqaured
a football coach starts at the 35-yard line(A) and walks to the 15-yard line (B). He turns around and walks to the 40-yard line (C). He turns aorund again and walks back to the 0-yard line (D). He turns around once more and walks back to the 25-yard line (E). this completing his 10 minutes of pacing. The coaches average speed is
11.0 y/min
A cannonball is launched from the ground at an angle of 30 degrees above the horizontal and a speed of 30 m/s. Ideally (no air resistance) the ball will land on the ground with a speed of
20 m/s
An object will definitely have potential energy if it is
At rest above the ground (a non-zero height) moving above the ground (a non-zero height)
At the instant a horizontally pointed cannon is fired, a cannonball held at the cannon's side is released and drops to the ground. Which cannonball strikes the ground first?
Both cannonballs fall the same vertical distance with the same accelertation g and therefore strike the ground at the same time.
The study of low temp phenomena
Cryogenics
Two objects of identical mass begin from rset at the same height at the top of two different hills. The hills are inclined at two different angles. The objects are released from rest and slide to the bottom; resistance forces can be considered to be negligible. The object on top of hill ____ will have the greatest speed at the bottom of the incline.
Hill A
Which of the following variations will increase the kinetic energy of an object?
Increase the object's mass Increase the object's speed
When you look at the speedometer in a moving car, you can see the car's
Instantaneous Speed
Which has more mass, a kilogram of feathers or a kilogram of iron?
Masses are equal
One possible unit of speed is
Miles per hour, kilometers per hour, centimeters per minute
At the instant a ball is thrown horizontally with a large velocity, an identical ball is dropped from the same height. Which ball hits the ground first?
Neither- they both hit the ground at the same time
If you drop a feather and a coin from the same height in a vacuum tube, which will reach the bottom of the tube first? Ignore air resistance
Neither- they reach the bottom at the same time
A tennis ball and a solid steel ball the same size are dropped at the same time. In the absense of air resistance, which ball has the greater acceleration?
Nonsense! they both have the same acceleration
The branch of physics that deals with light and vision
Optics
As a pendulum swings back and forth
PE is transformed into KE KE is transformed into PE At the lowest part of its swing, its energy is all kinetic At the end points of its swing, its energy is all potential
The study of subatomic particles
Particle physics
The study of a phase of matter distinct from solids, liquids, and gases (It is an electically neutral, highly ionized gas composed of ions, electrons, and neutral particles)
Plasma physics
A tennis ball and a solid steel ball with the same diameter are dropped at the same time. Which ball has the greater force acting on it?
The steel ball
State the law of conservation of momentum
The total momentum of all objects before a collision or explosion must be equal to the total momentum of all objects after.
The study of the relationships and conversions of heat and other forms of energy
Thermodynamics
Galileo found that a ball rolling down one inclined plane would roll how far up another inclined plane?
To nearly the same height as where it originally started
If a horse pulls on a wagon at rest, the wagon pulls back equally on the horse. Can the wagon be set into motion?
Yes, because there is a net outside force acting on the wagon.
In the absence of air resistance, objects in free fall move at constant
acceleration
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 ball is thrown into the air at some angle between 0 and 90 degrees. At the very top of the ball's path, its velocity is
entirely horizontal
In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because
the time of impact is increased
The horizontal component of a projectile's velocity is independent of
the vertical component of its velocity
Momentum of a system is conserved only when
there is no net external force acting on the system
The law of inertia states that an object
will continue moving at the same velocity unless an outside force acts on it will continue moving in a straight line unless an outside force acts on it that is not moving will never move unless a force acts on it at rest will remain at rest unless acted on by an outside force
All simple machines ideally work on the principle that
work input equals work output
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