# Examples of Newton’s Second Law

**Second Law of Newton**is related to the movement of a body. Explain the

**force that must be applied**to the mass that forms it

**to move it**with a certain acceleration. His statement, universally known, reads as follows:

*“If one or more forces are applied to a body, it acquires an acceleration that is directly proportional to the magnitude of the resulting force, and takes the same direction.”*

This Law is of great importance for the study of the movement of bodies close to the earth’s surface, such as artificial satellites that orbit the Earth. It also serves to describe and study the movement of the planets, extremely massive bodies. The formula that explains Newton’s Second Law is:

**F = m * a**

Where:

- F: is the force required by the body to be moved.
- m: is the mass of the body.
- a: is the acceleration taken by the body when it is moved.

Since the mass of a body is constant, the force to be applied (F) and the acceleration (a) it takes are taken as variables. If any of them are unknown, it can be solved for the equality to calculate it based on the others.

### Newton’s Second Law and weight

The **weight** is the **force** exerted by a body on the surface, product of its mass (m) and the acceleration of gravity (g). It is due to the **gravitational attraction** that a body requires a force to be moved or transported from one point to another on the planet. This force is described by Newton’s Second Law as follows:

**W = m * g**

Where:

- W: is the force required by the body to be moved. It is the same as what it exerts on the earth’s surface, that is, the weight.
- m: is the mass of the body.
- g: is the acceleration of gravity, which influences the body by gravitational attraction.

- The acceleration that a body acquires in free fall.
- The distance and speed at which a satellite must be positioned to maintain its orbital motion around the Earth.
- Determine the necessary force that must be applied to a train to accelerate it to 100 km per hour in 10 minutes.
- Calculate the force and angle a barrel must have for your bullet to hit a target.
- Calculate the speed that an airplane must have to stay in the air.
- Determine the motion of the planets around the Sun.
- Determine the force that must be applied on a slope so that the rate of ascent and descent is constant.
- Calculate the force that a support must exert on an object to prevent it from falling.
- Calculate the force of a rocket to get into orbit.
- Calculate the force that a trailer must have to move its load.
- The weight of a gold bar.
- The weight of mercury inside a flask.
- The weight of a car must be overcome with a hydraulic jack or hydraulic station.
- The weight of the carriages of a train is overcome by the steam engine in front of them all.
- The weights of two well-balanced loads on a scale are identical.
- The force exerted by a wrecking ball against the wall of a building. If it is older, it will be able to knock it down.
- The force with which a ship’s propellers propel it across the surface of the sea.
- The force that divers apply to their fins to propel themselves through the water.
- The weight of a cart pulled by a horse.
- The centrifugal force of rotating amusement rides.