VIDEO: Newton's law of force explained simply

Newton's law of force - this is how you understand the relationship

• Movements and, of course, changes in movement have a cause: external forces act on a body. Without such powers, you would not be able to accelerate a car or fire a bullet.
• In his second Law (often referred to as Newton's law of force) now a connection between the Body given acceleration (i.e. the change in speed) and the external force found.
• The law is in words "force is mass times acceleration" and in the formulas of the physics F = m * a. F means the force (in the unit Newton (N)), m the mass of the body (in kilograms (kg)) and a the acceleration (in the unit "meter per second square (m / s²)).
• Note that acceleration is defined as a change in speed over time. This results in the unit m / s², which takes a bit of getting used to.

The law of force in use - a calculated example

Newton's law of force should be illustrated using the example (from zero to 100). A car is accelerated from a standstill to a speed of v = 100 km / h. This process takes 12 seconds (yes, it's not one of those super sporty types). What force has to be applied if the car weighs 1,300 kg?

• First you convert the speed into the unit m / s: v = 100 km / h = 27.78 m / s (: 3.6).
• Now calculate the acceleration. The speed change from a standstill is 27.78 m / s. You need 12 seconds for this. So a = 27.78 m / s / 12 s = 2.315 m / s².
• According to Newton's law of force, you need the force F = m * a = 1300 kg * 2.315 m / s² = 3009.5 N.

When doing such tasks, make sure that you always calculate with the units kilograms, meters and seconds!