Regents Physics Review

#1

Vectors

Scalar Vector

Magnitude(size) only Magnitude(size) AND Direction

Distance Displacement

Speed Velocity

Mass Weight

Work Force

Momentum

Scalar is to vector as

(1) speed is to velocity

(2) displacement is to distance

(3) displacement is to velocity

(4) speed is to distance

What are the magnitudes of the

horizontal and vertical

components?

A model airplane heads due east at 1.50 meters per second, while the

wind blows due north at 0.70 meter per second. The scaled diagram

below represents these vector quantities.(June 2011)

66 Using a ruler, determine the scale used in the vector diagram. [1]

67 On the diagram above, use a protractor and a ruler to construct a vector to represent the

resultant velocity of the airplane. Label the vector R. [1]

68 Determine the magnitude of the resultant velocity. [1]

69 Determine the angle between north and the resultant velocity. [1]

A dog walks 8.0 meters due

north and then 6.0 meters due

east.

Using a metric ruler and the vector diagram, determine the scale used in the

diagram. [1]

On the diagram above, construct the resultant vector that represents the

dog’s total displacement. [1]

Determine the magnitude of the dog’s total displacement. [1]

Calculate the magnitude of the component of the 60.-newton force that is

parallel to the horizontal surface. [Show all work, including the equation and

substitution with units.] [2]

A baseball player runs 27.4 meters from the batter’s box to first base,

overruns first base by 3.0 meters, and then returns to first base.

Compared to the total distance traveled by the player, the magnitude of

the player’s total displacement from the batter’s box is

(1) 3.0 m shorter (2) 6.0 m shorter (3) 3.0 m longer (4) 6.0 m longer

A child walks 5.0 meters north, then 4.0 meters east, and finally 2.0

meters south. What is the magnitude of the resultant displacement of the

child after the entire walk?

(1) 1.0 m (2) 5.0 m (3) 3.0 m (4) 11.0 m

As the angle between two concurrent forces decreases, the magnitude of the

force required to produce equilibrium

(1) decreases (2) increases (3) remains the same

Which is a vector quantity?

(1) speed (2) work (3) mass (4) displacement

A soccer player kicks a ball with an initial velocity of 10. meters per second at an

angle of 30.° above the horizontal. The magnitude of the horizontal component

of the ball’s initial velocity is

(1) 5.0 m/s (2) 8.7 m/s (3) 9.8 m/s (4) 10. m/s

Regents Physics Review

#2

Motion, Velocity, Acceleration

(See Review Book P. 10-17)

Velocity is the change in displacement per unit time.

Velocity is a vector, it must include a direction such as

+,-, left, right, up, down, north, south, etc.

Speed is simply the change in distance over time

regardless of direction. Speed is a scalar.

Uniform Velocity = constant velocity; not changing.

Average Velocity = Total displacement / Total time

Acceleration = change in velocity over time.

Acceleration is a vector.

Equations from

Reference Tables:

Distance vs. Time graphs

Dis

tan

ce

Time

Slope = velocity

Straight line = constant velocity

= NOT accelerating

Distance vs. Time graphs

Dis

tan

ce

Time

Slope = velocity = 0

Straight HORIZONTAL line = 0 velocity

= NOT moving

Distance vs. Time graphs

Dis

tan

ce

Time

Slope = velocity

Curved line = changing velocity = acceleration

Ve

locity

Time

Slope = acceleration

Velocity vs. Time graphs

Straight line = uniform acceleration (e.g. gravity)

A 25-newton weight falls freely from rest from the

roof of a building. What is the total distance the

weight falls in the first 1.0 second?

(1) 19.6 m (3) 4.9 m

(2) 9.8 m (4) 2.5 m

If a car accelerates uniformly from rest to 15

meters per second over a distance of 100. meters,

the magnitude of the car’s acceleration is

(1) 0.15 m/s2 (2) 1.1 m/s2 (3) 2.3 m/s2 (4) 6.7 m/s2

Projectile Motion

When you throw an object into the air (projectile):

1. The X component of the velocity is constant (does not change)

2. The Y component of the velocity starts out large, slows down to 0,

then increases back to where it started.

3. What goes up, must come down…in the same amount of time. This

statement means that if it takes 4 seconds for an object to hit the ground

after it is thrown, then the object must have taken 2 seconds to get to the

top and 2 seconds to get back to the ground.

Vy

Vx

Vx

Vx

Vy

Vy Vy

Vx Vx

Vy= 0

Vx = Vcos Θ

Vy = Vsin Θ V

Θ

Summary

For projectile motion, remember the following:

1. Time up = Time down.

2. The projectile reaches its highest point midway through its

flight. (half the time & half the horizontal distance)

3. At the highest point, the vertical velocity = 0 m/s

4. Gravity affects only the vertical velocity.

5. The horizontal velocity is constant. (stays the same)

6. The shape of the path is a parabola.

The diagram below represents a ball being kicked by a foot and rising at an

angle of 30.0 from the horizontal. The ball has an initial velocity of 5.0

meters per second. [Neglect friction.]

A. What is the magnitude of the horizontal component of the ball's initial

velocity?

(1) 2.5 m/s (2) 4.3 m/s (3) 5.0 m/s (4) 8.7 m/s

B. As the ball rises, the vertical component of its velocity

(I) decreases (2) increases (3) remains the same

A rocket is launched at an angle of 60° to the horizontal.

The initial velocity of the rocket is 500 meters per

second. [Neglect friction.]

A. The vertical component of the initial velocity is

(1) 250 m/s (2) 433 m/s (3) 500 m/s (4) 1000 m/s

B. Compared to the horizontal component of the rocket's

initial velocity, the horizontal component after 10

seconds would be

(1) less (2) greater (3) the same

60 Determine the magnitude of the horizontal component of the velocity of the car

at point B. [Neglect friction.] [1]

61 Determine the magnitude of the vertical velocity of the car at point A. [1]

62 Calculate the magnitude of the vertical displacement, dy, of the car from point A

to point B. [Neglect friction.] [Show all work, including the equation and substitution

with units.] [2]

Time to “A” = 0.50 s

Time to “B” = 1.00 s

11 A ball is thrown vertically upward with an initial

velocity of 29.4 meters per second. What is the

maximum height reached by the ball? [Neglect friction.]

(1) 14.7 m (2) 29.4 m (3) 44.1 m (4) 88.1 m

Regents Physics Review

#3

Newton’s Laws, Forces, Friction

(See Review Book P.22-33)

Newton’s First Law of Motion: The Law of Inertia

An object will resist any change in its state of motion.

An object at rest will stay at rest; an object in motion will stay moving in a

straight line at a constant speed unless acted on by an unbalanced force.

Mass is the measure of an object’s inertia.

Newton’s Second Law of Motion: Force, Mass, and Acceleration

An unbalanced force causes an object to accelerate: F = ma

Equilibrium: All forces are balanced.

Newton’s Third Law of Motion: Action and Reaction

For every force there is an equal force in the opposite direction.

Newton’s Law of Universal Gravitation: All matter attracts other matter.

Fg = G m1 m2 / r2

.

Weight is a force caused by gravity:

F = ma F = mg On Earth, g = 9.81 m/s2

Friction is a force that opposes the motion of an

object and depends upon the type of surfaces that

are in contact with each other.

Friction can be:

“sliding” or “rolling”

“static” or “kinetic”

Each surface has its own coefficient of friction.

An object on an inclined plane has several forces acting upon it:

Weight, Normal Force, Force parallel to the plane, and Friction.

1. Force parallel to plane

2. Friction

3. Normal Force (perpendicular to plane

4. Weight

1.

2.

3.

4.

Centripetal Force

Inertia tends to keep the object in a straight line.

Centripetal Force: Force toward the center of a circle.

The result is circular motion.

Inertia

Centripetal

Force

12 The diagram below represents a mass, m, being swung clockwise at

constant speed in a horizontal circle.

At the instant shown, the centripetal force acting on mass m is directed

toward point

(1) A (2) B (3) C (4) D

7 The magnitude of the centripetal force acting on an object traveling in a

horizontal, circular path will decrease if the

(1) radius of the path is increased (3) direction of motion of the object is reversed

(2) mass of the object is increased (4) speed of the object is increased

8 The centripetal force acting on the space shuttle as it orbits Earth is equal to the

shuttle’s

(1) inertia (2) momentum (3) velocity (4) weight

A student and the waxed skis he is wearing have a combined weight of 850

newtons. The skier travels down a snow--covered hill and then glides to the

east across a snow-covered, horizontal surface.

53 Determine the magnitude of the normal force exerted by the snow on the

skis as the skier glides across the horizontal surface. [1]

54–55 Calculate the magnitude of the force of friction acting on the skis as the

skier glides across the snow-covered, horizontal surface. [Show all work,

including the equation and substitution with units.] [2]

70–71 Calculate the elongation of the spring produced by the suspended 2.00-

kilogram mass. [Show all work, including the equation and substitution with

units.] [2]

72–73 Calculate the total elastic potential energy stored in the spring due to the

suspended 2.00-kilogram mass. [Show all work, including the equation and

substitution with units.] [2]

13 As shown in the diagram below, an open box and its contents have a combined

mass of 5.0 kilograms. A horizontal force of 15 newtons is required to push the box

at a constant speed of 1.5 meters per second across a level surface.

The inertia of the box and its contents increases if there is an increase in the

(1) speed of the box

(2) mass of the contents of the box

(3) magnitude of the horizontal force applied to the box

(4) coefficient of kinetic friction between the box and the level surface

Regents Physics Review

#4

Momentum, Energy

Work, Power

Momentum: Mass x Velocity

Momentum is a vector quantity because velocity is a vector.

Formula: p = mv

Law of Conservation of Momentum: Total momentum of a system is conserved…all

the “pieces” of momentum must be accounted for and add up to the total you started

with.

Total Momentum before a collision = Total Momentum after a collision

Impulse = Force x time J = Ft

Impulse = change of momentum: Ft = mv

Energy is the capacity to do work. Potential= “stored up” Kinetic = moving

Work = a change in energy (potential or kinetic)

Work = force x distance.

Work can only be done if the force is in the same direction as the direction of motion!

Power = work / time or “How fast you do work.”

The diagram below represents two masses before and after they collide. Before

the collision, mass mA is moving to the right with speed v, and mass mB is at rest.

Upon collision, the two masses stick together.

Write an expression for V’ (the velocity after the collision.)

A 0.149-kilogram baseball, initially moving at 15 meters per second, is brought

to rest in 0.040 second by a baseball glove on a catcher’s hand. The magnitude

of the average force exerted on the ball by the glove is

(1) 2.2 N (2) 2.9 N (3) 17 N (4) 56 N

A 3.1-kilogram gun initially at rest is free to move. When a 0.015-kilogram

bullet leaves the gun with a speed of 500. meters per second, what is the

speed of the gun?

(1) 0.0 m/s (2) 2.4 m/s (3) 7.5 m/s (4) 500. m/s

Calculate the magnitude of the impulse applied to a 0.75-kilogram cart to

change its velocity from 0.50 meter per second east to 2.00 meters per second

east. [Show all work, including the equation and substitution with units.] [2]

A bicycle and its rider have a combined mass of 80. kilograms and a speed of 6.0

meters per second. What is the magnitude of the average force needed to bring the

bicycle and its rider to a stop in 4.0 seconds?

(1) 1.2 x102 N (2) 3.2 x102 N (3) 4.8 x102 N (4) 1.9 x103 N

Calculate the kinetic energy of a particle with a mass of 3.34 × 10-27 kilogram

and a speed of 2.89 × 105 meters per second. [Show all work, including the

equation and substitution with units.] [2]

Which statement describes the kinetic energy and total mechanical energy of a block

as it is pulled at constant speed up an incline?

(1) Kinetic energy decreases and total mechanical energy increases.

(2) Kinetic energy decreases and total mechanical energy remains the same.

(3) Kinetic energy remains the same and total mechanical energy increases.

(4) Kinetic energy remains the same and total mechanical energy remains the same.

Which graph represents the relationship between the gravitational potential energy

(GPE) of an object near the surface of Earth and its height above the surface of

Earth?

A ball is dropped from the top of a cliff. Which graph best represents the

relationship between the ball’s total energy and elapsed time as the ball falls to

the ground? [Neglect friction.]

A 1200-kilogram car moving at 12 meters per second collides with a 2300-

kilogram car that is waiting at rest at a traffic light. After the collision, the cars lock

together and slide. Eventually, the combined cars are brought to rest by a force of

kinetic friction as the rubber tires slide across the dry, level, asphalt road surface.

Calculate the speed of the locked-together cars immediately after the collision.

[Show all work, including the equation and substitution with units.] [2]

Calculate the magnitude of the frictional force that brings the locked-together cars

to rest. [Show all work, including the equation and substitution with units.] [2]

The diagram below shows a toy cart possessing 16 joules of kinetic energy

traveling on a frictionless, horizontal surface toward a horizontal spring.

If the cart comes to rest after compressing the spring a distance of 1.0 meter,

what is the spring constant of the spring?

(1) 32 N/m (2) 16 N/m (3) 8.0 N/m (4) 4.0 N/m

The diagram below represents a 155-newton box on a ramp. Applied force F causes

the box to slide from point A to point B.

What is the total amount of gravitational potential energy gained by the box?

(1) 28.4 J (2) 279 J (3) 868 J (4) 2740 J

A vertically hung spring has a spring constant of 150. newtons per meter. A

2.00-kilogram mass is suspended from the spring and allowed to come to rest.

Calculate the elongation of the spring produced by the suspended 2.00-kilogram

mass. [Show all work, including the equation and substitution with units.] [2]

Calculate the total elastic potential energy stored in the spring due to the

suspended 2.00-kilogram mass. [Show all work, including the equation and

substitution with units.] [2]

Regents Physics Review

#5

Waves

Waves • Transverse Wave

• Longitudinal (Compression) Wave

• Standing waves

• Velocity = Frequency x Wavelength

• Superposition, Phase

• Reflection

• Refraction

• Normal

• “Bend toward the Normal,” “Bend awwy from the Normal”

• Diffraction

• Polarization

• Angle of Incidence = Angle of Reflection

• Angle of Refraction

• Index of Refraction

• Spectrum

Transverse Wave (Electromagnetic,Light)

Crest or Peak

Valley or Trough

Wavelength

Longitudinal or Compression Wave (Sound)

Wavelength Compression

“squeezed together”

Rarefaction

“spread apart”

Standing Wave

Node Antinode

What is the total number of nodes and antinodes in the

standing wave?

(1) 3 nodes and 2 antinodes

(2) 2 nodes and 3 antinodes

(3) 5 nodes and 4 antinodes

(4) 4 nodes and 5 antinodes

What is the wavelength of this standing wave?

(1) 2.15 m (2) 4.30 m (3) 6.45 m (4) 8.60 m

The superposition of the waves produces the greatest positive displacement of

the medium from its rest

position at point

(1) A (2) B (3) C (4) D

The angle of reflection for the light ray is

(1) 25° (2) 35° (3) 50.° (4) 65°

Reflection

Refraction

Diffraction: “Bending” around corners.

69 Measure the angle of incidence for the light ray to the nearest degree. [1]

70 Calculate the angle of refraction of the light ray when it enters the Lucite

block. [Show all work, including the equation and substitution with units.] [2]

71 What is the angle of refraction of the light ray as it emerges from the Lucite

block back into air? [1]

65 A wave generator having a constant frequency produces parallel wave fronts in

a tank of water of two different depths. The diagram below represents the wave

fronts in the deep water. As the wave travels from the deep water into the shallow

water, the speed of the waves decreases.

On the diagram below, use a straightedge to draw at least three lines to represent

the wave fronts, with appropriate spacing, in the shallow water. [1]

Slows down

Shorter Wavelength

Same Frequency

55 A periodic wave travels at speed v through medium A. The wave passes

with all its energy into medium B. The speed of the wave through medium B

is v/2 . On the diagram below, draw the wave as it travels through

medium B. [Show at least one full wave.] [1]

(Slows down, shorter wavelength)

Base your answers to questions 72 through 74 on the information and diagram

below. A ray of monochromatic light having a frequency of 5.09 × 1014 hertz is

incident on an interface of air and corn oil at an angle of 35° as shown. The ray is

transmitted through parallel layers of corn oil and glycerol and is then reflected from

the surface of a plane mirror, located below and parallel to the glycerol layer. The

ray then emerges from the corn oil back into the air at point P.

72 Calculate the angle of refraction of the light ray as it enters the corn oil from air.

[Show all work, including the equation and the substitution with units.] [2]

73 Explain why the ray does not bend at the corn oil-glycerol interface. [1]

74 On the diagram above, use a protractor and straightedge to construct the

refracted ray representing the light emerging at point P into air. [1]

Regents Physics Review

#6

Electricity & Magnetism

Vocabulary and Terms

• Charge

• Like Poles or Charges, Unlike Poles or Charges

• Electric Field

• Electrostatic Force

• Potential Difference = Voltage = V

• Current = amperage = I

• Resistance = Ohms = R symbol = Ω

• Ohm’s Law: V = IR R = V/I I = V/R

• Resistivity: ρ (rho)

• Series Circuit

• Parallel Circuit

• Power

• Energy (Work)

Deflects toward opposite charge.

North South

Positive Negative

Like Poles Repel

Magnetic Field

On the diagram below, draw at least four electric field lines in the region

between the two positively charged particles. [1]

Series Circuit: Current is constant, Voltage adds up, Resistance adds up.

Parallel Circuit: Voltage is constant, Current adds up, 1/Req = 1/R1+1/R2 +…

23 Which circuit has the smallest equivalent resistance?

Base your answers to questions 59 and 60 on the information and diagram

below. A 10.0-meter length of copper wire is at 20°C. The radius of the wire

is 1.0 × 10–3 meter.

59 Determine the cross-sectional area of the wire. [1]

60 Calculate the resistance of the wire. [Show all work, including the equation

and substitution with units.] [2]

Regents Physics Review

#7

Modern Physics

Dual Nature of Light: Particle and Wave

Photon: Particle of light

Strong Force: Force holding nucleus (protons and neutrons) together

Weak Force: Force between electrons and the nucleus

Photoelectric Effect: Light can cause electrons to be emitted from matter.

Quarks: Up, Down, Top, Bottom, Charm, Strange

Bohr Model: Atoms seen like the solar system

Rutherford Experiment: Atom is mostly empty space with a solid nucleus.

Energy Levels

Planck’s Constant

+ Alpha(+)

The Atom

J.J.Thomson: “Plum Pudding” Model

Rutherford: Gold Foil Experiment…

empty space and nucleus

Bohr: Planetary Model

Energy Levels

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