Newton’s 2 nd Law of Motion By: Heather Britton

Newton’s 2 nd Law of Motion Newton’s 2 nd Law of Motion states... The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. The direction of the acceleration is the direction of the net force acting on the object

Newton’s 2 nd Law of Motion Or more simply stated ΣF = ma Sigma (Σ) - the sum of.... F - force measured in Newtons 1 Newton = 1 kgm/s 2

Newton’s 2 nd Law of Motion Matter - anything that has mass and occupies space Mass - the measure of the amount of matter on object contains It is also the measure of the inertia a body contains

Newton’s 2 nd Law of Motion The more inertia a body contains the harder to change its state of motion The SI unit for mass (m) is the kilogram (kg) Mass is not the same as weight

Newton’s 2 nd Law of Motion A body’s mass does not change depending on location Weight is a force and is gravity dependent Weight can change as a gravitational field changes

Newton’s 2 nd Law of Motion Weight is mass multiplied by the acceleration of gravity Since the moon has only about 1/6 the gravity of Earth you would weigh 1/6 of your Earth weight on the moon However, your mass would not change

Newton’s 2 nd Law of Motion There can be many different types of forces including F g - force of gravity or weight F T - force caused by tension F f - forces caused by friction

Newton’s 2 nd Law of Motion Example 1 What net force is required to accelerate a 1500 kg race car at 3.0 m/s 2 ?

Newton’s 2 nd Law of Motion Example 2 An artillery shell has a mass of 55 kg. It leaves a 1.5 m gun barrel with a velocity of 770 m/s. What is the force on the shell while it is in the gun barrel?