What's Up Doc

This post will be a review of the physics topic hoping to aid you in the test tomorrow.

Newton's three laws of motion:

1. Law of Inertia: An object will stay at rest or move in a straight line with a constant velocity unless acted upon by an external force.
2. F=ma An object of a given mass will accelerate at a rate proportionate to the force.
3. For every action, there is an equal opposite reaction.

Speed vs. Velocity

• Speed is scalar (size only)
• Speed = Distance/Time
• Velocity is a vector (size and direction)
• Velocity = Displacement/Time

Displacement is the shortest distance between the starting point and the current point while distance is the total path traveled.

Acceleration is the rate the velocity changes with respect to time.
Formula for average acceleration is (difference in velocity)/time.

Equations of motion:

Where v is the final velocity, u is the initial velocity, a is acceleration and t is time

Where r is displacement.

Newton's Universal Gravitational Law
The force between two bodies can be calculated by using the following formula

Where m1 and m2 are the masses of the two bodies and r is the distance between the centre of the two bodies. G is the Universal gravitational constant.

The gravity of a body can be calculated by using the following formula

Centripetal Force
In centripetal motion, the acceleration is equal to the velocity squared divided by the radius.
Therefore F=ma become F=m(v^2/r)

Calculating Average Acceleration using a ticker timer.
A ticker timer will make 50 marks per second in other words, the time between the dots is equivalent to 1/50 of a second. To find the average acceleration you would have to find the initial velocity (distance between the first two dots/(1/50)) and the final velocity (distance between last to dots/(1/50)). Find the difference between the two velocities and then divide that by the total time taken.

Other notes:
The pronumeral for distance is 's' not 'd'
Displacement is 'r' not 'd'
Speed/Velocity is 'v'not 's'

Good luck for the test tomorrow