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