# Newtonian Mechanics (true or false)

• rechitzy
In summary: YOUR HELP!!In summary, the conversation discusses various statements related to work, acceleration, and force. The group agrees that the statement about the work required to lift a mass being dependent on its speed is false. They also discuss the concept of inertial reference frames and conclude that the statement about the acceleration of an object being the same in all inertial reference frames is true. In regards to kinetic energy, they determine that it can change without net work being done on it. However, the statement about the work done by a constant force being equal to the magnitude of the force times the distance is not clear and may be false. Finally, they agree that using a simple machine can reduce the force required to do a task, but it does not necessarily
rechitzy

## Homework Statement

1.The work required to lift a mass one meter depends on the speed at which it is raised..

2.The acceleration of an object is same in all inertial reference frames.

3.A particle's kinetic energy can change without having any net work done it.

4.The work done by a constant force acting on an object is equal to the magnitude of the force times the distance the object moves.

5.Less power is required while lifting a box up quickly than while slowly lifting it.

6.A simple machine may reduce the force required to do a task

## The Attempt at a Solution

FTTTFT
FFFTFT
FTTTFF
FTFTFT

Let's examine each one separately. You're pretty sure that #1 is false, and you're right--it doesn't depend on speed. #4 is not worded clearly, but technically it might be false. Consider the scenario where an object attached to a string is swung in a circle. The tension in the string is always perpendicular to the object's motion, so it does no work. However, the object does move a non-zero distance under the influence of a constant force.

You knew #5 is false, which is good: it is. Can you explain what you think about the other questions? Why are you not sure?

#6 A simple machine may reduce the force required to do a task, i believe it reduces the force, thinking of a pulley it reduces the force but not the work because you are still doing the work right? It might take longer but you are reducing the force that you have to apply in order to do a task.

#2 i am really confused i don't know what inertial reference frames mean but i thought it was false because it referred to ALL

#3 A particle's kinetic energy can change without having any net work done it, it is talking specifically about net work, not just work so it confuses me and that's why i went from T to F to T and to F again

rechitzy said:
#6 A simple machine may reduce the force required to do a task, i believe it reduces the force, thinking of a pulley it reduces the force but not the work because you are still doing the work right? It might take longer but you are reducing the force that you have to apply in order to do a task.

I agree with your logic. But the statement isn't addressing anything about work. It's only dealing with force.

#2 i am really confused i don't know what inertial reference frames mean but i thought it was false because it referred to ALL

I think I can help you with this one. "Inertial frame" means a frame of reference that is not accelerating, itself. A frame of reference called an "inertial frame" can be traveling at an arbitrary constant velocity, but the frame is not accelerating.

So in question #2, you are not comparing the acceleration to an object relative to something else (namely a frame of reference) which is also accelerating. The fact that the term "inertial frame" is used, means that you are only comparing the acceleration of the object to things (frames) which are not accelerating (even though they may have different constant velocities).

#3 A particle's kinetic energy can change without having any net work done it, it is talking specifically about net work, not just work so it confuses me and that's why i went from T to F to T and to F again

I'm not sure I follow you on this one. Can you think of any example where a particle's kinetic energy changes with no net work done on it? (Well, using Newtonian mechanics, that is)

on 6 i believe it is true because it does reduces the force it takes to do a task

on 2 is true

on 3 the net work done on an object is equal to the change in its kinetic energy so it will be false for 3

is this right?

rechitzy said:
on 6 i believe it is true because it does reduces the force it takes to do a task

on 2 is true

on 3 the net work done on an object is equal to the change in its kinetic energy so it will be false for 3

is this right?

I believe your logic is sound.

Got it! it is right

THANKS YOU SO MUCH collinsmark AND ideasrule I REALLY APPRECIATED

## 1. Is Newtonian Mechanics still considered valid today?

Yes, Newtonian Mechanics is still considered valid for most everyday situations. However, it has been replaced by more complex theories in extreme situations such as in the realm of quantum mechanics and at high speeds approaching the speed of light.

## 2. Does Newtonian Mechanics only apply to objects on Earth?

No, Newtonian Mechanics applies to objects in any environment as long as they are moving at speeds much slower than the speed of light.

## 3. Can Newtonian Mechanics explain the movement of objects in the universe?

Yes, Newtonian Mechanics can accurately explain the movement of objects in the universe as long as they are not moving at extremely high speeds or in extreme gravitational fields.

## 4. Is Newtonian Mechanics the same as classical mechanics?

Yes, Newtonian Mechanics is often referred to as classical mechanics as it was developed by Isaac Newton in the 17th century and is still widely used today.

## 5. Are Newton's laws of motion the only principles in Newtonian Mechanics?

No, Newton's laws of motion are the most well-known principles in Newtonian Mechanics, but there are other principles such as the law of universal gravitation and the conservation of momentum that also play a crucial role in the theory.

• Introductory Physics Homework Help
Replies
5
Views
758
• Introductory Physics Homework Help
Replies
11
Views
4K
• Introductory Physics Homework Help
Replies
2
Views
3K
• Introductory Physics Homework Help
Replies
2
Views
1K
• Introductory Physics Homework Help
Replies
25
Views
2K
• Introductory Physics Homework Help
Replies
2
Views
2K
• Introductory Physics Homework Help
Replies
7
Views
2K
• Introductory Physics Homework Help
Replies
7
Views
1K
• Introductory Physics Homework Help
Replies
5
Views
4K
• Introductory Physics Homework Help
Replies
3
Views
2K