Newton’s Three Laws of Motion
First Law: Balanced Forces means there will be No change in Velocity.
- Balanced Forces are when the forces Resultant Force is equal to zero. e.g. xN – xN = 0N.
- According to the First Law of Motion this statement must always be true.
Second Law: A Resultant Force Means there will be Acceleration.
- The object on which a Resultant Force is acting upon will always Accelerate according to Newton’s Second Law.
- Basically, if you push something, it will move and thus Accelerate.
Third Law: If object A exerts a Force on object B then object B will exert an equal opposing Force on object A.
- Essentially, what it means is that if you push something like a toy car, then that toy car is going to push back against you with equal Force. This is called a Reaction Force.
So, what does General Force mean in I/GCSE Physics?
The formula for General Force (as in the force that occurs from the kinetic energy of more conceivable Force, like pushing a door shut) is extremely useful. With it, we can calculate, and thus predict, things like how much Force will be exerted upon the car in a car crash, saving countless lives. The formula is F = ma (Force = Mass × Acceleration)
A car has lost control of its breaks and is heading for a concrete wall. Its Mass is 2000kg
and it is Accelerating at 20m/s. With what amount of force will the car hit the wall?
F = ma, therefore we simply sub in our values for Mass and Acceleration into the formula. Tremendously easy! 20 × 2000 = 40000N (this is an extremely large Force and 20m/s Acceleration is an insanely fast rate at which to Accelerate)
Another car comes speeding, crashing into the back of the first car. The car crashes with
a Force of 28000N and it’s mass was 300kg. What was the car’s Acceleration?
Formula for Force: F = ma (Force = Mass × Acceleration)
End of this topic!