SPH3U - Final Exam Review

Scalar

Scalar

A measured quantity with its unit

Distance

The total length of the path travelled by an object

Vector

A measured quantity with its unit and direction

Position

The location of an object based on a reference point

Displacement

Distance with a direction; A change in position

What are the four ways to solve for total displacement?

• Same direction - vector subtraction

• Different directions - vector addition

• Drawing scale diagrams

• Component method

Speed

How quickly the object gets from one point to another, m/s

Velocity

The vector form of speed, m/s

Acceleration

How quickly an object’s velocity changes over time, m/s²

Instantaneous Acceleration

The rate of change of velocity at a specific instance of time

Acceleration due to gravity

9.8m/s²

Uniform Velocity

Motion at a constant speed in a straight line

Non-Uniform Velocity

Motion that is not at a constant speed or not in a straight line

Position-Time Graph

A graph describing the motion of an object, where the slope is velocity

How can the slope of a curved line be found?

Draw a tangent line, and then solve using two points

Instantaneous Velocity

The velocity of an object at a specific instant in time

Velocity-Time Graph

A graph describing the motion of an object, with the velocity on the vertical axis and time on the horizontal axis, where the area is distance travelled, and slope is acceleration

Uniform Acceleration

Acceleration where the amount and direction is constant

Acceleration-Time Graph

A graph describing the motion of an object, where the area is velocity

What is the velocity at the maximum height of a projectile motion?

0m/s

How do you solve for 2D motion using the component method?

• Find x and y components of each vector using trigonometry

  • Asinθ = y

  • Acosθ = x

• Group x components and add (consider directions)

• Group y components and add (consider directions)

• Find the total using the Pythagorean Theorem

  • A = √[(total x)²+ (total y)²]

• Use tangent to solve for direction

What is the slope of an acceleration/sin x graph?

Gravity

How do projectile motions behave in regards to horizontal velocity?

Time is independent, and range is increased

How does an increase in height affect projectile motion?

An increased height results in an increased range and time

How does mass affect projectile motion?

It does not affect it

Projectile Motion

The motion of a projectile is guided by gravity only and assumes no air resistance

How can projectile motion be solved?

It can be split into horizontal and vertical components

• Horizontal uses distance/time = velocity

• Vertical uses big 5 equations

• Time is equivalent

• Vertical acceleration is gravity

How does horizontal velocity behave in a projectile motion?

Horizontal velocity remains constant

Force

A push or pull vector quantity on a body, measured in Newtons (N)

Contact Forces

Forces that make contact, including friction, air resistance, applied force, tension, and normal force

Applied Force

A literal push or pull

Friction

A force caused by two objects rubbing together, which acts in the opposite direction of movement

Air Resistance

An upward force that resists the downward force of gravity, also called air friction or drag

Tension

A pulling force caused by objects connected by a rope or cable, which is constant throughout the entire length

Normal Force

The upward force caused by the surface an object lies upon, which works against the force of gravity, and will always be perpendicular to the surface

Free Body Diagrams

Simplified diagrams that show the magnitude and direction of forces

Balanced Forces

An object in equilibrium due to all forces cancelling each other out, causing the object to remain at rest or a constant velocity

Unbalanced Forces

An object is not in equilibrium and will accelerate in the direction of the net force vector

Resultant Vector

The total of adding vectors

Newton’s First Law

An object at rest will remain at rest unless it is acted upon by an external unbalanced force. An object in motion with constant velocity will continue to do so, unless acted upon by an unbalanced force

Inertia

The resistance of an object to change from its current motion or rest

How does mass affect inertia?

More mass creates more inertia

Newton’s Second Law

An unbalanced force applied to an object causes the object to accelerate

According to Newton’s Second Law, how is acceleration affected?

An increase in force increases acceleration, but an increase in mass decreases acceleration

1 Newton

The amount of force for 1kg to have an acceleration of 9.8m/s²

What is the accelerated speed of an object falling?

The force of gravity (F_g = (g)(m))

Newton’s Third Law

For every action force, there is an equally sized reaction force. The reaction force is opposite in direction. They form a force pair.

What is the net force of a stationary object?

0

How can the net force be found?

Using vector addition, or (m)(a)

How can a two mass pulley system be solved?

There are two individual systems, but the same force of tension is acting on each

If two objects are pushed against one another, what should the notation be?

F₁₂ and F₂₁

How can a system where objects attached by cables and there is no friction be solved?

• All objects will have the same acceleration

• To find the net force, acceleration, or mass of the entire system, use the same net force and acceleration, and use the total mass

• To calculate the tension in the rope closest to the end, the net force of the last object is equivalent to the tension, so use its mass and acceleration to solve

• To calculate the tension in the rope closest to the front, use the total mass of all of the following objects, multiplied by their acceleration. The net force is equivalent to the tension

Terminal Velocity

The maximum speed at which an object can fall, and forces are balanced

What measurement do scales read?

The normal force, which can be found through the vector addition of the net force and the force of gravity

If an object experiencing an applied force does not move, what is the force of static friction?

The same as the applied force

What happens as falling speed increases?

Air resistance increases

What happens to falling objects in a vacuum?

They fall at the same time

What is the gravitational field dependent on?

Mass

Weight

The force of gravity acting on an object

Static Friction

The friction that occurs when the applied force has not yet succeeded in causing action

Kinetic Friction

The opposing force when two surfaces are in motion

Does it take more force to get something moving or keep it moving?

Getting something moving

What is the relationship of kinetic friction and speed?

It is a constant force independent of speed

What affects friction?

Normal forces and surface materials

What is the coefficient of friction?

The number, that when multiplied by the normal force, gives the force of friction. This is dependent on the specific materials.

Work

When a force is applied to an object, so it moves a certain distance, measured in Joules

Is there work at 90 degrees?

No

What type of work occurs below 90 degrees?

Positive work

What type of work occurs above 90 degrees?

Negative work

What is the area of a force/distance graph?

Work

Net Work

The sum of all work, considering both positive and negative work

Energy

The ability to cause change or to do work

Mechanical Energy

The energy an object has due to its motion or position

Kinetic Energy

The energy of motion, which increases as speed increases

Potential Energy

The stored energy of an object due to its position or condition

Gravitational Potential Energy

The potential energy that increases when an object’s height increases, due to its place and presence of a gravitational field

Elastic Potential Energy

Type of potential energy that increases when an object is stretched

Electromagnetic Energy

Energy that travels in waves, such as light or x-rays, which does not need to travel through matter

Sound Energy

Energy that is carried by vibrations in matter

Chemical Energy

Energy in food and fuel, where chemical bonds are broken down to release energy

Nuclear Energy

Energy that is released when an atom is split in half or fused

Sun

The main source of earth’s energy

What does kinetic energy depend on?

Speed and mass

Work-Energy Principle

The net amount of mechanical work done on an object equals the object’s change in kinetic energy

What does gravitational potential energy depend on?

The strength of gravity, vertical position, and mass

Law of Conservation of Energy

The total amount of energy in the universe is conserved. There is a certain total amount of energy, and this total never changes. New energy cannot be created out of nothing, and existing energy cannot disappear. The energy that exists can only be changers from one form to another.

Efficiency

A measure of the amount of useful energy compared to the total energy

Renewable Energy

A substance with an unlimited supply or a supply that can be replenished as the substance is used in the energy-transforming processes

Non-Renewable Energy

A substance that cannot be replenished as it is used

Power

The rate at which energy is transferred; the rate at which work is done, measured in Watts

Kinetic Molecular Theory

The theory that describes the motion of molecules or atoms in a substance in terms of kinetic energy

• Everything is made of particles

• Particles move

• Forces of attraction are between particles

• Temperature is the average kinetic energy of the particles

The conversion between Celsius and Kelvin

To convert: K -273 = C

Thermal Energy

The total amount of kinetic and potential energy of the particles in an object

Heat

The transfer of heat energy; the flow of thermal energy from one place to another

Three methods of heat transfer

Conduction, convection, radiation

Conduction

A method of heat transfer within an object or between two objects in contact

Convection

The transfer of energy by the movement of higher energy particles to an area of lower energy

Radiation

The transfer of heat through infrared waves

Thermal Conductor

Materials that allow heat to flow through them more easily

Thermal Insulator

Materials that do not allow heat to flow easily