Select The Correct Answer.What Would Kelly's Weight Be In Newtons If Her Mass Is 70 Kilograms?A. $70 \times G$ B. 70 C. $70 \times G^2$ D. $70 \times G^2$ E. 70

Feb 27, 2025 by ADMIN 167 views

**Understanding Weight in Newtons: A Physics Perspective**

Introduction

In physics, weight is a measure of the force exerted on an object due to gravity. It is an essential concept in understanding various physical phenomena, including motion, energy, and momentum. In this article, we will delve into the concept of weight in newtons, specifically focusing on Kelly's weight if her mass is 70 kilograms.

What is Weight?

Weight is the force exerted on an object by gravity. It is a measure of the gravitational pull on an object, which depends on its mass and the acceleration due to gravity. The weight of an object is typically denoted by the symbol 'W' and is measured in newtons (N).

The Formula for Weight

The formula for weight is given by:

W = mg

where W is the weight, m is the mass of the object, and g is the acceleration due to gravity.

Acceleration Due to Gravity

The acceleration due to gravity, denoted by 'g', is a constant that depends on the location on Earth. On the surface of the Earth, the acceleration due to gravity is approximately 9.8 meters per second squared (m/s^2).

Kelly's Weight in Newtons

Now, let's apply the formula for weight to Kelly's situation. If her mass is 70 kilograms, we can calculate her weight in newtons as follows:

W = mg = 70 kg x 9.8 m/s^2 = 686 N

Selecting the Correct Answer

Based on the calculation above, we can see that Kelly's weight in newtons is 686 N. Now, let's examine the answer choices:

A. $70 \times g$ B. 70 C. $70 \times g^2$ D. $70 \times g^2$ E. 70

The correct answer is A. $70 \times g$ . This is because the formula for weight is W = mg, and we can substitute the value of g (9.8 m/s^2) to get W = 70 kg x 9.8 m/s^2 = 686 N.

Conclusion

In conclusion, Kelly's weight in newtons can be calculated using the formula W = mg, where m is her mass and g is the acceleration due to gravity. By substituting the values, we get W = 70 kg x 9.8 m/s^2 = 686 N. Therefore, the correct answer is A. $70 \times g$ .

Additional Tips and Tricks

Always remember that weight is a measure of the force exerted on an object by gravity, and it depends on the object's mass and the acceleration due to gravity.
The formula for weight is W = mg, where W is the weight, m is the mass, and g is the acceleration due to gravity.
The acceleration due to gravity, denoted by 'g', is a constant that depends on the location on Earth. On the surface of the Earth, the acceleration due to gravity is approximately 9.8 m/s^2.

Frequently Asked Questions

What is weight in physics? Weight is the force exerted on an object by gravity.
What is the formula for weight? The formula for weight is W = mg, where W is the weight, m is the mass, and g is the acceleration due to gravity.
What is the acceleration due to gravity? The acceleration due to gravity, denoted by 'g', is a constant that depends on the location on Earth. On the surface of the Earth, the acceleration due to gravity is approximately 9.8 m/s^2.

References

Halliday, D., Resnick, R., & Walker, J. (2013). Fundamentals of physics. John Wiley & Sons.
Serway, R. A., & Jewett, J. W. (2018). Physics for scientists and engineers. Cengage Learning.

Glossary

Weight: The force exerted on an object by gravity.
Mass: A measure of the amount of matter in an object.
Acceleration due to gravity: A constant that depends on the location on Earth, denoted by 'g'.
Physics Q&A: Weight and Mass ================================

Introduction

In our previous article, we discussed the concept of weight in newtons and how to calculate it using the formula W = mg. In this article, we will answer some frequently asked questions related to weight and mass.

Q&A

Q: What is the difference between mass and weight?

A: Mass and weight are two related but distinct concepts in physics. Mass is a measure of the amount of matter in an object, whereas weight is the force exerted on an object by gravity. For example, a person's mass remains the same on Earth and on the moon, but their weight changes due to the difference in gravitational acceleration.

Q: How do you calculate weight in newtons?

A: To calculate weight in newtons, you can use the formula W = mg, where W is the weight, m is the mass, and g is the acceleration due to gravity. For example, if a person's mass is 70 kilograms and the acceleration due to gravity is 9.8 meters per second squared, their weight would be W = 70 kg x 9.8 m/s^2 = 686 N.

Q: What is the acceleration due to gravity on Earth?

A: The acceleration due to gravity on Earth is approximately 9.8 meters per second squared (m/s^2). However, this value can vary slightly depending on the location on Earth and the altitude above sea level.

Q: How does the acceleration due to gravity affect weight?

A: The acceleration due to gravity affects weight by changing the force exerted on an object by gravity. For example, on the moon, the acceleration due to gravity is about one-sixth of that on Earth, which means that objects weigh less on the moon than they do on Earth.

Q: Can you give an example of how to calculate weight in newtons?

A: Let's say we want to calculate the weight of a book that has a mass of 2 kilograms. If the acceleration due to gravity is 9.8 m/s^2, we can use the formula W = mg to calculate the weight:

W = 2 kg x 9.8 m/s^2 = 19.6 N

So, the weight of the book is 19.6 newtons.

Q: What is the difference between weight and force?

A: Weight and force are related but distinct concepts in physics. Weight is the force exerted on an object by gravity, whereas force is a more general term that can refer to any push or pull on an object. For example, a person's weight is the force exerted on them by gravity, but they can also experience other forces, such as the force of friction or the force of a push or pull.

Q: Can you give an example of how to calculate force in newtons?

A: Let's say we want to calculate the force exerted on a person who is being pushed by a friend. If the person's mass is 70 kilograms and the acceleration due to gravity is 9.8 m/s^2, we can use the formula F = ma to calculate the force:

F = 70 kg x 9.8 m/s^2 = 686 N

However, this is not the force exerted by the friend, but rather the force exerted by gravity on the person. To calculate the force exerted by the friend, we would need more information, such as the magnitude and direction of the force.