If you went to high school, you probably have at least a general idea of who Isaac Newton was and what he did. Isaac Newton was an astronomer, mathematician, and physicist. He was a triple-threat, with his primary contribution to science being that he founded three laws of motion. We’ll cover his second with this calculator. 

What most people remember him for was his theory of gravity. Isaac sat beneath an apple tree, only for an apple to fall on his head. He then came to realize that free fall to Earth and celestial bodies movement is a result of gravity.

That’s where his three laws of motion come in. They describe the movement of objects under force. We’ll cover the three laws below, before calculating Newton’s Second Law.

The First Law of Motion
Unless acted upon by a non-zero force, an object will stay still, in a straight line, and with no motion. 

The Second Law of Motion
Among many things, Newton’s Second Law of Motion covers the force of acceleration for an item. 

The Third Law of Motion
When an object exerts force onto something, the second item experiences similar effects. This law epitomizes the rule of a reaction for every action.

What is Newton’s Second Law of Motion?

Even though there are three laws of motion, we will cover the second law here. It relates to the acceleration of an object in proportion to its net force (F) and mass (m). The following equation explains it:

a = F / m

What the letters mean:

A (in m/s2) = object acceleration 
F (in N) = the force on an object
M (in kg) = an object’s mass

Newton’s law incorporates many rules. The objects react to force directed upon them, but the effect of the force depends on the object’s inertia. The way an object behaves can also change, depending on how willing it is to change its velocity. The bigger the object’s mass, the larger its inertia.

How Do You Calculate Force?

When you understand what the second law of motion is, you then need to find an expression for the force. It can be hard to calculate acceleration, so change the formula to include velocity and acceleration. 

The formula would look like this:

F = m x (v_f = v_i) x dt

What the letters mean:
v_f (in m/s) = final velocity 
v_i (in m/s) = initial velocity 
dt (in s) = velocity change timeframe

When you use that formula, you can calculate force. If you use the data backward, you can discover the change in velocity.

Using the Calculator for Newton’s Second Law

You can use Newton’s equations to make calculations by hand, but a calculator can be a quicker option. You can calculate force with Newton’s Second Law in mere seconds by entering the data you have.

Let’s say you want to stop a truck. The truck weighs 20,000 kilograms and moves at 90 kilometers per hour. You have to stop it in 30 seconds with a final velocity of 50 km/hr. According to Newton’s Second Law calculator, you need -7,407 N of force to stop the vehicle.