Laws of Physics
Newton’s First Law
An object moves at a constant velocity unless an unbalanced force acts on it.
Friction force that is acting on an object that is not moving
Static friction
Net unbalanced force generates this
Motion
Term used when gravity is the only force acting on an object
Free fall
These laws relate the change in an object’s motion with the forces acting on it
Newton’s Laws
Another name for a kg*m/s2
Newton (N)
The momentum of a 90 kg linebacker sprinting at 2.5 m/s
p = mv
p = 90 kg * 2.5 m/s
p = 225 kg m/s
As the distance between two masses decreases, this happens with the gravitational attraction
Increases
Newton’s Third Law
For every action force there is an equal and opposite reaction force
The weight here on Earth for a student with a mass of 55kg
w = mg
w = 55 kg * 9.8 m/s2
539 N
This is conserved when two objects collide in a closed system
Momentum
A force exerted toward the center of a curved path
Centripetal force
This is also known as The Law of Inertia
Newton’s First Law
The two main forces acting on a skydiver
Gravity and air resistance
This non-linear path of motion describes horizontal velocity and vertical acceleration
Projectile Motion
A car accelerating at 2 m/s2 has a force of 3000 N, it must have this mass
m = F/a
m = 3000 N / 2 m/s2
1500 kg
The three forms of the equation for Newton’s Second Law
a=F/m; F=ma; m=F/a
The four types of friction discussed in this class
Static, sliding, fluid, rolling
The total momentum before a collision equaling the total momentum after a collision is described by this
Law of conservation of momentum
You find yourself on the Moon; this happens to your mass; this happens to your weight
Mass remains the same; weight decreases
When a bus hits a bug which has a greater force upon impact? The bug or the bus?
The forces are equal but accelerations are not due to differences in mass