Free falling body & Projectile motionPhysics

Free fallInNewtonian physics,free fallis any motion of a body where itsweightis the onlyforceacting upon it.A body is said to be in free fall when it falls under the gravitational attraction of the Earth without any other forces acting on it.

Without air resistance, all objects irrespective of mass and shape would fall vertically downwards with the same acceleration, known as acceleration of free fall or gravitational acceleration, g.

The value of g is assumed to be 9.81m/s^2 in the downwards direction.

Since the value of g is constant, equations for uniformly accelerated motion derived above can be applied for vertical motion under gravity by substituting a= -g (assuming vectors in the upward direction as positive)

v = u-gts = 0.5(u + v)ts = ut- 0.5(gt^2)v^2 = u^2 2gs

Examples of free falling objects: -An object dropped at the top of adrop tube -Falling of a coin after being released in a vacuum tube with the air inside removed

Examples of non-free falling objects: -Flying in an aircraft: there is also an additional force of lift.

Projectile Motion

A projectile is a body that is projected with an initial velocity and travels in the vertical plane under the action of gravity.

Based on the figure below, the projectile motion of a body projected with a velocity u at an angle 0 to the horizontal can be resolved into 2 independent linear motion, one along the x-axis, and vertical motion along the y-axis

Analysis of the horizontal motion along the x-axis and the vertical motion along the y-axis

The horizontal distance OP is know as the range, R

The end

Prepared by Lionel & Badrul

Special thanks ms siti esah bt mohd