# Describe the relationship between force inertia and acceleration

### Big Ideas for Forces and Motion

Inertia and Inertial mass is found out using Newtons Second law. Meaning force and acceleration are directly proportional to each other (f∝a). Sometimes there are times of acceleration and deceleration, in which the object is All objects tend to resist motion; this tendency is called Inertia. Newton's second law describes the relationship between mass, force and acceleration. What is the connection between forces and motion? resultant force = mass × acceleration Inertia. The mass of an object is measured in kilograms (kg). The mass of an object is The ratio of force over acceleration is called inertial mass.

If smoother planes were used, the ball would roll up the opposite plane even closer to the original height. Galileo reasoned that any difference between initial and final heights was due to the presence of friction. Galileo postulated that if friction could be entirely eliminated, then the ball would reach exactly the same height. Galileo further observed that regardless of the angle at which the planes were oriented, the final height was almost always equal to the initial height.

## How does Newton's second law relate to inertia?

If the slope of the opposite incline were reduced, then the ball would roll a further distance in order to reach that original height. Galileo's reasoning continued - if the opposite incline were elevated at nearly a 0-degree angle, then the ball would roll almost forever in an effort to reach the original height.

And if the opposing incline was not even inclined at all that is, if it were oriented along the horizontalthen Newton's first law of motion declares that a force is not needed to keep an object in motion. Slide a book across a table and watch it slide to a rest position. The book in motion on the table top does not come to a rest position because of the absence of a force; rather it is the presence of a force - that force being the force of friction - that brings the book to a rest position.

In the absence of a force of friction, the book would continue in motion with the same speed and direction - forever! Or at least to the end of the table top.

• Newton's Second Law
• Inertia and Mass

A force is not required to keep a moving book in motion. In actuality, it is a force that brings the book to rest. And similarly, rows 4 and 5 show that a halving of the mass results in a doubling of the acceleration if force is held constant.

Acceleration is inversely proportional to mass.

### Inertia and Mass

Whatever alteration is made of the net force, the same change will occur with the acceleration. Double, triple or quadruple the net force, and the acceleration will do the same. On the other hand, whatever alteration is made of the mass, the opposite or inverse change will occur with the acceleration.

Double, triple or quadruple the mass, and the acceleration will be one-half, one-third or one-fourth its original value. The Direction of the Net Force and Acceleration As stated abovethe direction of the net force is in the same direction as the acceleration.

Thus, if the direction of the acceleration is known, then the direction of the net force is also known.

Consider the two oil drop diagrams below for an acceleration of a car. Theory of impetus[ edit ] See also: Conatus In the 14th century, Jean Buridan rejected the notion that a motion-generating property, which he named impetus, dissipated spontaneously.

## What is the connection between forces and motion? - OCR 21C

Buridan's position was that a moving object would be arrested by the resistance of the air and the weight of the body which would oppose its impetus. Despite the obvious similarities to more modern ideas of inertia, Buridan saw his theory as only a modification to Aristotle's basic philosophy, maintaining many other peripatetic views, including the belief that there was still a fundamental difference between an object in motion and an object at rest.

Buridan also believed that impetus could be not only linear, but also circular in nature, causing objects such as celestial bodies to move in a circle.

Buridan's thought was followed up by his pupil Albert of Saxony — and the Oxford Calculatorswho performed various experiments that further undermined the classical, Aristotelian view. Their work in turn was elaborated by Nicole Oresme who pioneered the practice of demonstrating laws of motion in the form of graphs.

Shortly before Galileo's theory of inertia, Giambattista Benedetti modified the growing theory of impetus to involve linear motion alone: Classical inertia[ edit ] Galileo Galilei The principle of inertia which originated with Aristotle for "motions in a void" states that an object tends to resist a change in motion. According to Newton, an object will stay at rest or stay in motion i.

### Second Newton's Law. Mass, Inertia, Acceleration, Force.

The Aristotelian division of motion into mundane and celestial became increasingly problematic in the face of the conclusions of Nicolaus Copernicus in the 16th century, who argued that the earth and everything on it was in fact never "at rest", but was actually in constant motion around the sun. A body moving on a level surface will continue in the same direction at a constant speed unless disturbed.

The first physicist to completely break away from the Aristotelian model of motion was Isaac Beeckman in Unless acted upon by a net unbalanced force, an object will maintain a constant velocity.