Chapter 2: Foundations of physics

Phyics AS Level - OCR Gateway A completed ♡

What is a systematic error?

Errors of the same measurement in the same direction from the true value, following a pattern / trend / bias. It is “off” by a certain amount.

What is a random error

Errors of measurment of differing direction and magnitude around the mean value.

How to fix a systematic error?

Correct it via calculation.

How to fix a random error?

By finding the:

• mean

• removing anomalies

• drawing a graph

When is a measurement accurate?

A measurement is accurate if it is close to the true value.

When is a measurement precise?

It is precise when there is very little spread about the mean value.

What is resolution?

Smallest change in the quanity being measured.

What does it mean by a greater resolution?

A better (i.e. smaller) resolution.

When is an experiment repeatable?

• same method

• same equipment

• same result

• same person

  
  

When is an experiment reproducable?

• different person or and

• different equipment and

• same result

What is the radium of an atom?

1 × 10^-10

What is the radius of the Earth?

1 × 10⁷

What is the radius of the sun?

1 × 10⁹

What is the radius of the whole universe?

1 × 10²⁶

What is a scalar quantity?

Only has magnitude (size)

What is a vector quantity?

Has both magnitude (size) and direction

What are some examples of scalar quantites?

• Temperature

• Speed

• Distance

What are some examples of vector quantites?

• Velocity

• Acceleration

• Displacement

What is the distance of an object?

How an object travelled but not the direction

What is the displacement of an object?

How far an object is from where it started, and its direction

What is the rule for adding vectors in the same direction?

Add the size

Direction is the same

What is the rule for adding vectors in the opposite direction?

Subtract the smaller vector from the bigger one

Direction is the same as the biggest vector

How to find the size of 2D vectors?

Pythagoras

How to find the direction of 2D vectors?

Tan