Physics Unit 2: Accelerated Motion Notes

Acceleration = gradient of the velocity-time graph.

Displacement = area under the velocity-time graph.

The conditions to apply equations of motion are:

1. The object should travel in a straight line.
2. Object has constant acceleration.

The equations of motion are:

• v = u + at (definition of acceleration)
• s = [(u + v) / 2] x at^2 (definition of average velocity)
• s = ut + 1/2 x at^2
• v^2 = u^2 + 2as

In Projectile motion, we resolve the velocity in X and Y directions. In the Y-direction, we apply equations of motion because gravity acts vertically.

When air resistance is neglected, there is no acceleration in the horizontal direction. Hence, we do not apply equations of motion in the X-direction; instead, we use the velocity = displacement/time formula.

In projectile motion, the vertical velocity at the highest point is zero.

Also, the time taken to reach the highest point = the time taken to reach the ground. (As gravity is the only force acting on the object.)