3.motion in one plane

Motion in one plane 

Projectile Motion: Any object in flight after being thrown  with some velocity is called a projectile and its motion is called projectile motion.

Path length: This is the actual distance

travelled by the object during its motion.

1) Average velocity: This is defined as the 

displacement of the object during the time 

interval over which average velocity is 

being calculated, divided by that time 

interval.

2) Average speed: This is defined as the 

total path length travelled during the time 

interval over which average speed is being 

calculated, divided by that time interval.

3. Instantaneous velocity: Instantaneous

velocity of an object is its velocity at a given instant of time.

4. Instantaneous speed: Instantaneous speed is the speed of an object at a given instant of time t .

5. Acceleration: Acceleration is defined as

the rate of change of velocity with time.

 

6. Free fall: When a body starts with zero velocity at a certain height from the ground and falls under the influence of the gravity of the Earth, it is said to be in free fall. 

Always Remember: 

For uniform rectilinear motion, i.e., for an 

object moving with constant velocity along 

a straight line 

1. The average and instantaneous 

velocities are equal.

2. The average and instantaneous speeds 

are the same and are equal to the 

magnitude of the velocity.

For nonuniform rectilinear motion

1. The average and instantaneous 

velocities are different.

2. The average and instantaneous speeds 

are different.

3. The average speed will be different 

from the magnitude of average velocity.

Conical pendulum:  In a simple pendulum a mass m is suspended by a string of length l and moves along an arc of a vertical circle.

Relative Velocity: Relative velocity between two objects moving in a plane can be defined in a way similar to that for objects moving along a straight line.