# How to Calculate Weight and Force in Physics: Astronaut Case Study

• Destiny153
In summary, the conversation is about learning the three laws of motion in a physics class, with a focus on the use of math in solving problems. The problem given involves calculating the weight of an astronaut before lift off and when they are 6400 km above the Earth's surface. The formula Fnet = ma is mentioned, with a request for help in understanding it.
Destiny153
so in my physics class, we are learning about the 3 laws of motion and all that jazz bla bla bla, i get all that stuff, just not the stuff where it comes to math. i suck at math! so we had homework, no duh, and well I am stuck, can i please have some help! anyone??

hear is the problem:

An astronaut has a mass of 50 kg.

A.) how much does she weigh before lift off?
B.) when her space vehicle is 6400 Km. above the Earth's suface, she will weigh one quarter of what she weighed on earth. what does she weigh at this point?

so there you are, ps i know this formula but i don't understand it. Fnet = ma

net force= mass times acceleration? righ?

Destiny153 said:
so in my physics class, we are learning about the 3 laws of motion and all that jazz bla bla bla, i get all that stuff, just not the stuff where it comes to math. i suck at math! so we had homework, no duh, and well I am stuck, can i please have some help! anyone??
First, this is not the homework section.Second ,the three laws of motions are not "bla bla bla"
Destiny153 said:
hear is the problem:

An astronaut has a mass of 50 kg.

A.) how much does she weigh before lift off?
B.) when her space vehicle is 6400 Km. above the Earth's suface, she will weigh one quarter of what she weighed on earth. what does she weigh at this point?

so there you are, ps i know this formula but i don't understand it. Fnet = ma

net force= mass times acceleration? righ?
For A. you just use your formula with the appropriate acceleration.For part B what you wrote is nonsense.

## 1. What is the difference between weight and force?

Weight and force are often used interchangeably in everyday language, but they actually have different meanings in physics. Weight is a measure of the gravitational force exerted on an object by a celestial body, such as the Earth. Force, on the other hand, is a measure of the push or pull on an object caused by interactions with other objects.

## 2. How do I calculate weight?

To calculate weight, you need to know the mass of an object (in kilograms) and the acceleration due to gravity (in meters per second squared). Weight is then calculated by multiplying the mass by the acceleration due to gravity. The formula for weight is W = mg, where W is weight, m is mass, and g is the acceleration due to gravity.

## 3. How do I convert between different units of weight and force?

To convert between units of weight and force, you can use conversion factors. For example, 1 pound (lb) is equal to 4.45 newtons (N), so you can multiply a weight in pounds by 4.45 to get the equivalent weight in newtons. Similarly, 1 kilogram (kg) is equal to 9.8 newtons (N), so you can multiply a mass in kilograms by 9.8 to get the equivalent weight in newtons.

## 4. What is the difference between mass and weight?

Mass and weight are often confused, but they are not the same thing. Mass is a measure of the amount of matter in an object, while weight is a measure of the force acting on an object due to gravity. Mass is constant and does not change, while weight can change depending on the strength of gravity.

## 5. How does force affect motion?

According to Newton's Second Law of Motion, force is directly proportional to acceleration. This means that the greater the force acting on an object, the greater its acceleration will be. Additionally, force can also change the direction of motion of an object. This is why objects accelerate towards the Earth due to the force of gravity, and why objects can change direction when pushed or pulled by a force.

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