How Do You Describe Force and the Laws of Motion? Newton’s Laws of Motion They describe the relationship between a body and the forces acting upon it, and its motion in response to said forces.forces motion

First Law (Law of Inertia) An object that is at rest will stay at rest unless an external force acts upon it. An object that is in motion will not change its velocity unless an external force acts upon it.

Second Law F = m × a The acceleration of a body is directly proportional to, and in the same direction as, the force acting on the body, and inversely proportional to its massaccelerationforcemass a = F/m A force is any influence that causes an object to undergo a certain change, either concerning its movement or direction. In other words, a force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate.objectmassvelocitystate of rest accelerate

The Unit of Force is the Newton (N) Definition: The amount of force needed to accelerate 1 kilogram of mass at the rate of 1 meter per second squaredkilogram meter per second squared Newton = kilogram (meter/second)/second 1N = 1kg m/s 2

Third Law When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction to that of the first body.

Momentum Definition: product of the mass and velocity of an objectmass velocity p = mv Units: kilogram meter/second kg m/s

Newton’s Law of Universal Gravitation Every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.point massforce directly proportional G is the gravitational constant

Calculation of Force Between the Earth and a 1kg Rock 10meters High F = Gm 1 xm 2 /r 2 G = 6.674x Ns 2 /kg M 1 = 5.972x10 24 kg M 2 = 1kg r = 6.341x10 6 m r 2 = 4.059x10 13 m 2 F = 9.8N a = F/m =9.8N/1kg = 9.8m/s 2