Physics is the…

Basic of all sciences. Its concepts are the foundation for all other sciences.

Mathematics is important to science because…

It gives a simple way to express complex relationships. It is unambiguous.

Difference between science and technology.

Science is a method of answering questions. Technology is a method of solving problems.

Fact

a close agreement by competent observers who make a series of observations of the same phenomenon

Law or Principle

A hypothesis that has been tested over and over again and is not contradicted

Theory

a synthesis of a large body of information that includes well-tested and verified hypotheses

Physics

The study of the nature of things such as motion, forces, energy, matter, heat, sound, light, and the composition of atoms

Why are equations often used in science?

Because they provide guides to thinking. They don’t have double meanings and provide a common language for the discussion of ideas.

Five general steps of the scientific method?

- Identify the problem.
- Create a hypothesis (an educated guess) about the answer.
- Predict the consequences of the hypothesis.
- Perform experiments to test your predictions.
- Formulate the simplest general rule that organizes the hypothesis, prediction, and experimental outcome.

1kg=

10N

10N=

2.2lbs

Vector quantity

A vector quantity is a quantity that describes both magnitude and direction.

Equilibrium rule

Whenever the net force on an object is zero, the object is said to be in mechanical equilibrium.

Two forces acting on a book at rest on a table

The weight of the book due to gravity acts downward. The support force provided by the table acts upward on the book.

Force

A push or pull on an object. Unit of force is N (newtons of gravity force).

Net force

The combination of all acting forces

When is something in equilibrium?

If an object moves at constant speed in a straight line then it is in equilibrium

Inertia is a way to measure…

how hard it is to change an object’s motion.

Mass

a measure of the amount of matter in an object. Unit of mass is kg.

Weight

A measure of the force of gravity on an object.

Equation relation to weight and mass.

Weight = mass * acceleration due to gravity. W=mg

Equation Newton’s second law of gravity

F=ma

(force = mass * acceleration). [kg * m/s^2]

m/s^2 =

N/kg

Newton’s first law.

Law of Inertia. A body in motion tends to remain in motion if no net force is exerted on the body in the direction of motion.

Copernicus’s idea

He thought that Earth and the other planets moved around the sun.

What did Galileo explain?

that a force is not necessary to keep an object moving

Friction

The force that acts between materials that touch as they move past each other. Irregularities in the surface that the object is touching obstructs motion and causes friction, which opposes motion.

What is a measure of inertia?

Mass. The more mass an object has, the more inertia it has and the more force is needed to change the state of motion.

A hypothesis must be…

testable. If it cannot be proven or disproven, it is outside the realm of science.

Tension

Stretching force

Scalar quantity

Can be described by magnitude only and has no direction.

Support force

Upward force that balances weight of an object on a surface. aka normal force.

Resultant

Sum of 2+ vectors

Acceleration

Means speed up, slow down or change direction. The rate at which velocity changes. Acceleration is around 10m/s^2 moving upwards, 9.8m/s^2 moving downwards

Speed

How fast something freely falls from rest after an elapsed time. Has both scalar and vector quantities.

Equation for falling in free fall (distance)

d = 1/2*gt^2. g=10m/s^2

Change in position

Motion

Change in motion

speed, velocity (w/ directional information)

Instantaneous speed

the speed at any instant.

Free fall

When an object moving under the force of only gravitational force

Elapsed time

The time passed since the beginning of any motion.

The instantaneous speed of an object at its highest point after it is thrown straight up into the air

zero

Distance

how far an object has fallen

Relative

when an object moves in motion with respect to the other object.

Speed equation

speed = distance/time. v = d/t

Average speed

ave. speed = (total distance covered)/(time interval)

Velocity

Speed in a given direction

Acceleration equation

acceleration = change of velocity/time interval

instantaneous speed equation

instantaneous speed = acceleration * elapsed time. v = gt

Vertical Direction velocity

(change in)y = v(0) + 1/2(a(y)t^2))

Horizontal direction change

(change in)x = v(0)t + 1/2(a(x)t^2))

Displacement

s = v(i)(change in)t + (a(change in)t)^2/2 s = distance