Physics Sem 1 Fall 2023 Study Guide-zions

Natural Motion

Motion that an object does naturally; caused by an internal quality that makes an object seek a "preferred" position without an applied force.

Unnatural Motion

Any motion that requires an applied force in order for the motion to be sustained.

Principle of Inertia

States that an object at rest tends to stay at rest, and an object in motion will continue in its current state of motion unless an outside agent acts on it.

Force

A push or pull; an agent that causes or opposes changes in motion of matter, or tends to do so.

Balanced Forces

When the sum of all simultaneous forces acting on an object equals zero; the forces cancel each other.

Unbalanced Forces

Forces that change an object's state of motion.

Equilibrant Force

A force that balances one or more other concurrent forces.

Equilibrant

A vector having the same magnitude as the unbalanced force sum but pointing in the opposite direction.

Weight

The force of gravity acting on an object.

Mass

Amount of matter in an object

Fundamental Forces

Inherently part of the atomic building blocks of matter.

Scientists have identified only four:

• Gravitational

• Electromagnetic

• Strong Nuclear

• Weak Nuclear

Gravitational Force

This attractive long-range force is proportional to the mass of objects and exerts its influence over theoretically infinite distances.

Electromagnetic Forces

A long-range force that is responsible for chemical bonding and other interactions of atoms and molecules.

Strong Nuclear Interaction Force

Binds together the particles in the nucleus; a short range force.

Weak Nuclear Interaction Force

It is involved in beta decay and other nuclear events in radioactivity; a short-range force.

Action-at-a-Distance forces

Model in which forces that do not require physical contact for transmission of the forces are thought to emanate from certain objects and matter in general.

Noncontact Forces

No physical contact is required to transmit or exert these forces.

i.e.: gravity and the electromagnetic forces.

Field Theory

This theory proposes that the objects impose properties on the space around them.

Exchange-Particle Theory

The exchange o virtual particles between matter creates the force.

Virtual Particles

Exchanged between matter with like characteristics. The exchange supposedly creates the force.

Contact (Mechanical) Forces

Forces that are transmitted only by physical contact between objects.

Tensile forces (tension)

Forces that tend to pull things apart.

Compressive Forces

Forces that tend to push things together or to crush.

Torsion

Twisting forces.

Friction

Forces that oppose motion between two objects in contact.

Shear Forces

Forces that tend to cause layers within matter to slide past one another.

Force Table

Demonstrates the addition of force vectors.

A device used to measure the equilibriant force.

Newton's Laws of Motion

Summarizes the principles of dynamics.

Systems

A part of the universe contained within an imaginary border that separates it from its surroundings in order to study it.

Set of related forces acting on an object.

Newton's First Law of Motion

An object at rest will remain at rest and an object in motion will remain in motion unless acted on by an outside, unbalanced force.

Mechanical Equilibrium

Occurs when the object is travelling at a constant velocity or is at rest (constant velocity = 0)

Newton's Second Law of Motion

The net force on an object is proportional to the product of its mass and acceleration.

∑F = ma

Newton's Third Law of Motion

For every force, there is an equal but opposite reaction.

Action-Reaction Force Pair

Two equal but opposite forces.

- All forces occur in pairs;

- Each force in an action-reaction pair has the same magnitude;

- Each force acts in the opposite direction in line with the other force pair;

- Each force acts on a different system.

An object flying through the air subject only to gravity

or

An object in free fall

What is a projectile?

parabola

What do we call the shape of a projectile's path through the air?

Yes → 9.8 m/s² down

Does a projectile have vertical acceleration?

No → Gravity is the only force acting on a projectile, and gravity doesn't pull horizontally.

Does a projectile have horizontal acceleration?

stays constant

The horizontal component of a projectile's velocity...

Changes by 9.8 m/s each second

On the way up it slows down by 9.8 m/s each second; on the way down it slows down by 9.8 m/s each second

The vertical component of a projectile's velocity...

45 degrees

When launching a projectile from ground level, what angle results in the greatest range?

90 degrees

When launching a projectile, what angle results in the greatest height?

range

The horizontal displacement of a projectile.

hang time

The total time a projectile spends in the air.

The one launched at the angle closer to 45 degrees

(assuming there's no air resistance)

If two projectiles are launched from ground level with the same initial speed but at different angles, the projectile that will land furthest away will be...

Have the same range

(assuming no air resistance)

If two projectiles are launched from ground level at complementary angles, they will...

Complementary Angles

Two angles whose sum is 90 degrees

15 m/s

(assuming you and your friend are about the same height)

(Taking air resistance into account, the final speed would be less than 15 m/s.)

If you throw a ball to your friend with a speed of 15 m/s, how fast will it be going when it gets to her if we neglect air resistance?

0 m/s

If you throw a ball straight up, what is its vertical velocity at the top of its path?

If you throw a ball into the air at a 45 degree angle, is its velocity zero at the top of its path?

No -- the ball's vertical velocity is zero, but the ball still has all the horizontal velocity you gave it when you threw it.

9.8 m/s² down

If you throw a ball straight up, what is the acceleration of the ball at the top of its path?

A projectile hits the ground with 3 m/s of horizontal speed and 4 m/s of vertical speed. How fast is it going?

5 m/s

The one affected by air resistance will have a smaller range, a smaller maximum height, and a shorter time in the air than the one in the vacuum chamber.

You fire two identical balls from ground level with the same initial speed and at the same angle, but one ball is in a vacuum chamber and the other is not. How will their hang time, range, and maximum height compare?

Pythagorean Theorem

a²+b²=c²

9.8 m/s² down

Acceleration due to gravity of all projectiles is always...

Acceleration: 9.8 m/s² down

All objects in free fall have the same...

Air restistance

The fluid friction experienced by objects falling through the air.

Vacuum Chamber

A container from which almost all of the air has been removed.

Drop (Free fall problems)

viy=0 ( initial velocity is zero)

same amount

(has to be thrown and caught at the same height)

It takes the object the ----- of time to rise as to fall not including air resistance

speed

An object returns to your hand with the same ----- it left with. But not the same velocity.

Velocity

Speed in a given direction

Displacement

Distance and direction of an object's change in position from the starting point.

Distance

How far an object moves in a given amount of time

Acceleration

The rate at which velocity changes

Time

A scalar so can be on the horizontal or vertical column

the farther the object will go

the higher the building...

zero

If the object is projected horizontally, the initial vertical velocity is...

dx = vt in the x direction

to find the range of a projectile you would use

dy = -1/2gt2

to find the height of a projectile use

6 seconds

a projectile is fired straight up at a speed of 30 m/s, the total time to return to its starting point is about

Launching a projectile at 45 degrees off the ground how far will it travel if the launch velocity is 30 m/s and it takes 5 sec

30 m/s x cos 45 or 21.2 m/s x5s = 106 m

30 m/s x cos 45 = 21.2 m/s

Launching a projectile at 45 degrees off the ground what will be the velocity in the x- direction if the launch velocity is 30 m/s?

the same magnitude as, and opposite in sign to, the velocity it had when thrown upwards

A ball thrown upward is caught when it comes back down. In the absence of air resistance, the acceleration of the ball when caught is

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

neither-they will reach the bottom at the same time

If you drop a feather and a coin at the same time in a vacuum tube (the absence of atmosphere) which will reach the bottom of the tube first?

Projectiles only accelerate in the ___________ direction

downward y-direction

the same as when it was at the top of its path

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)

Creation mandate

God created universe, mankind fell, redemption through Jesus

100m downrange

A cannonball is launched horizontally from a tower. If the cannon has a barrel velocity of 100 m/s, where will the cannonball be 1 second later?

Classical physics

Physics before quantum mechanics

Modern physics

Physics including quantum mechanics

Empirical science

Science based on observation and experiment

Operational science

Science focused on practical applications

Dominion science

Science in the context of God's dominion over creation

Quantum mechanics

Physics that deals with the behavior of particles at the atomic and subatomic level

Thermodynamics

Study of heat and energy transfer

Scientific method

A logical, systematic approach to the solution of a scientific problem

Metric conversions

Converting between different units of measurement in the metric system

kilo

1000

hecto

100

deka

10

base unit

1

deci

0.1

centi

0.01

milli

0.001

Radians

Unit of measurement for angles

sine

opposite / hypotenuse

cosine

adjacent / hypotenuse

tangent

opposite / adjacent