Unit B, Chapter 3, Lesson 4 What is Newton’s Second Law of Motion?

Mass, Force, and Acceleration It is easier to push or pull an object with less mass than an object with greater mass. –For example: pushing an empty desk needs less force than a desk filled with textbooks. Newton’s second law of motion states an object’s acceleration depends on the mass of the object and the size and direction of the force acting on it.

Mass, Force, and Acceleration Force =mass x acceleration –Force refers to the overall force given to an object. Mass is to the mass of the objects and acceleration to the objects change in velocity. An object accelerates in the direction of the force that acts on them.

Mass, Force, and Acceleration The greater the force applied, the faster the object accelerates. When a weaker force is given, the object will move slower –For example…when you push a person on roller skates, they will move faster with a greater force applied. When the acceleration of an object changes, the amount of force acting on the object also must be changing.

Falling Objects Aristotle, the Greek philosopher, claimed that the rate at which an object falls depended on its mass. –G–Galileo tested that theory by dropping two cannon balls at the same time. Aristotle's theory was wrong. Two objects dropped with different masses, should hit the ground at the same time. Mass has no control over the rate at which objects fall. Gravity pulls harder on the object with more mass, but inertia overpowers gravity. –T–The objects have the same amount of acceleration.

Falling Objects All falling objects have the same acceleration, unless air resistance affects them in some way. –When you drop a flat piece of paper, and a crumbled up paper, air resistance causes the flat piece of paper to fall slower. Skydivers use streamlining. Streamlining allows someone or something to increase their acceleration –When you streamline an object, you give it the smallest possible surface area