# Motion in 2 Dimensions

### Understanding Motion in 2 Dimensions

**Two-dimensional motion**occurs when an object moves in more than one direction or along more than one axis.- Two-dimensional motion can be analysed using
**vector quantities**such as displacement and velocity. - The vector quantities in two dimensions are described by their
**magnitude**(size) and**direction**. - When an object’s motion is along a curved path, it is described as
**projectile motion**.

### Vector Quantities

- A
**vector**is a physical quantity that has both magnitude and direction. - Examples of vector quantities include velocity, acceleration, and displacement.
- Vectors can be represented graphically using arrows, where the length of the arrow shows the magnitude and the direction of the arrow depicts the direction of the vector.

### Vector Addition and Resolution

**Vector addition**is the process of combining two or more vectors.- The
**resultant vector**is the vector that results from vector addition, it can also be found by drawing a line from the start of the first vector to the end of the last vector. **Vector resolution**involves breaking a vector down into its component vectors along the x and y axes.

### Projectile Motion

- A projectile is an object moving under the influence of gravity while its horizontal motion remains constant.
**Horizontal and vertical motions**of a projectile are independent of each other.- The
**trajectory**of a projectile is parabolic. - The maximum height, range, and time of flight of a projectile can be determined using appropriate equations of motion.

### Relative Velocity

**Relative velocity**refers to the velocity of one body in relation to another.- If two objects are moving in the same direction, their relative velocity is the difference between their velocities.
- If two objects are moving in opposite directions, their relative velocity is the sum of their individual velocities.

### Newton’s Laws of Motion

**Newton’s first law**(law of inertia) states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force.**Newton’s second law**states that the rate of change of momentum of a body is directly proportional to the force applied and occurs in the direction in which the force is applied.**Newton’s third law**states that for every action, there is an equal and opposite reaction.

### Understanding Problem-Solving in Kinematics

- Questions about motion in two dimensions are typically solved by breaking the problem into
**horizontal and vertical**components. - Each component can be analysed separately using the principles of kinematics; thereafter, the results are combined to give the final answer.
- Use of
**diagrams**is encouraged to help visualise and solve problems.