# Physics

by nrliman -
# 1. Chapter 3 : Forces & Pressure

## 1.1. Free-body diagrams

### 1.1.1. addition of parallel vectors

### 1.1.2. addition of non- parallel vectors

1.1.2.1. 1. Choose scale 2. Draw arrows to represent forces 3. Complete parallelogram 4. R.F is represented by the diagonal of the parallelogram. - magnitude = diagonal - direction= angle from horizontal line.

## 1.2. Pressure

### 1.2.1. SI Unit : Pa p = f/a

## 1.3. Motion of objects

### 1.3.1. Newton's 1st law of motion Every object will continue in its state of rest or uniform motion in a straight line unless a R.F acts on it.

1.3.1.1. Balanced forces

1.3.1.1.1. R.F = 0 Acceleration = 0 Object at rest will remain at rest. Object in motion will remain at constant velocity.

### 1.3.2. Newton's 2nd law of motion When a R.F acts on an object of constant mess, the object will accelerate in the direction of the R.F. R.F = ma

1.3.2.1. Unbalanced forces

1.3.2.1.1. R.F ≠ 0 Acceleration ≠ 0 Object at rest will move Object in motion will change its velocity

### 1.3.3. Newton's 3rd law of motion If body A exerts a force on body B, then body B will exert an equal & opposite force on body A.

## 1.4. Effects of force

### 1.4.1. A body at rest moves

### 1.4.2. A moving body increases in speed

### 1.4.3. A moving body decreases in speed

### 1.4.4. A moving body changes direction

# 2. Chapter 1 : Measurement

## 2.1. Physical quatity

### 2.1.1. can be measured and consist of a unit and magnitude.

## 2.2. Vector quatity

### 2.2.1. can be measured and consist of a unit, magnitude and direction.

## 2.3. Prefixes

### 2.3.1. cannot measure thin objects.

### 2.3.2. kilo - k mega - M giga -- tera - milli - m micro - nano - pico -- deci - d - 10^-1 centi - c - 10^-2

## 2.4. Vernier calipers

### 2.4.1. 0.01cm / 0.1mm

2.4.1.1. check for zero error!

2.4.1.2. check if the zero mark coincides with the zero mark on the vernier scale when the outside jaws touch each other.

## 2.5. Micrometer screw gauge

### 2.5.1. 0.01mm / 0.1cm

2.5.1.1. check for zero error!

2.5.1.2. check if the smallest reading is 0.00mm, where the spindle touches the anvil. +Below datum line - positive +Above datum line - negative

### 2.5.2. measure thick to thin objects.

# 3. Chapter 4 : Mass, Weight, Density

## 3.1. Mass

### 3.1.1. Amt. of substance in a body

### 3.1.2. Is a measure of inertia

## 3.2. Weight

### 3.2.1. The gravitational force acting on an object

### 3.2.2. SI Unit : N W = mg

### 3.2.3. Gravitational field strength is the gravitational force acting per unit mass.

3.2.3.1. Gravitational field is a region in which a mass experiences a force due to gravitational attraction.

## 3.3. Inertia

### 3.3.1. The reluctance of the object to change its state of rest or motion due to its mass.

## 3.4. Density

### 3.4.1. Mass per unit volume

### 3.4.2. SI Unit : kg/m^3 p = m/v

# 4. Chapter 2 : Kinematics

## 4.1. Scalars

### 4.1.1. Physical quantities with units and magnitude only.

### 4.1.2. Speed

4.1.2.1. Scalar quantity SI Unit : m/s

## 4.2. Vectors

### 4.2.1. Distance

4.2.1.1. SI Unit : m

### 4.2.2. Physical quantities with units, magnitude and direction.

### 4.2.3. Velocity

4.2.3.1. SI Unit : m/s Velocity = displacement/time

### 4.2.4. Acceleration

4.2.4.1. a = V-U / T

### 4.2.5. Displacement

## 4.3. Graphs

### 4.3.1. The gradient in distance - time graph gives the speed.

### 4.3.2. The gradient in Speed - time graph gives the acceleration.

### 4.3.3. The area under speed - time graph gives the distance.