Laws of Motion, some problems.

In summary, the conversation was about a new user introducing themselves and asking for help with a test on Newton's Laws of Motion. Three questions were also posted, with the first one asking for the average force on a particle moving on a circular path, the second one asking for the frictional force on a block, and the third one asking for the minimum speed of a rotor to prevent a person from slipping downward. The answers to the questions were (3√3 mv^2)/4πr, 0.1N, and √(g/μr) respectively. The user also mentioned having trouble with one of the answers and asked for clarification.
  • #1
The Precious
1
0
I'm new to this forum, so Hi! :) I have a test on Newton's Laws of Motion, the day after tomorrow and will appreciate any kind of help on these problems. Thank you very much, and nice to meet you all. :)

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Q1. A particle of mass m moves with constant speed v on a circular path of radius r. It starts from a point A and makes a 240 rotation when it comes at point B. What is the average force on it during it's motion from A to B? [Ans: (3√3 mv^2)/4πr ]

Q.2 A 1Kg block is kept on a 100 kg block. Coefficient of friction , μ=0.5
What is the frictional force acting on the 1Kg block? [Ans: 0.1N]

(I know this is very simple, but I am always ending up with an answer of 5N. Am I doing something wrong logically or is the answer given wrong?

Q.3 A person stands in contact against the inner wall of a rotor of radius r. The coefficient of friction between the wall and his clothes is μ and the rotor is rotating about vertical axis. What is the minimum speed of rotor so that the person des not slip downward? [Ans: √(g/μr) ]
 
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  • #2
One problem per one thread please.

In each problem, use the template.

Show your attempt.

Respect the rules and you will get help.
 

Related to Laws of Motion, some problems.

1. What are Newton's three laws of motion?

Newton's first law states that an object at rest will remain at rest and an object in motion will remain in motion with a constant velocity unless acted upon by an unbalanced force. Newton's second law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Newton's third law states that for every action, there is an equal and opposite reaction.

2. How do these laws apply to real-life situations?

These laws have numerous real-life applications. For example, Newton's first law explains why a seatbelt is necessary in a moving car, as it keeps passengers from continuing to move forward when the car suddenly stops. Newton's second law is used in the design of vehicles and structures, as it helps engineers determine the necessary amount of force to move an object. Newton's third law explains why we feel a recoil when shooting a gun, as the force of the bullet causes an equal and opposite reaction on the shooter.

3. What is the difference between mass and weight in relation to these laws?

Mass is the amount of matter in an object, while weight is the measure of the force of gravity acting on an object. These two concepts are often used interchangeably, but they are not the same. In relation to Newton's laws of motion, mass is directly proportional to an object's inertia, meaning an object with more mass will require more force to move. Weight, on the other hand, affects an object's acceleration due to gravity, but it is not a factor in the laws of motion themselves.

4. How can we calculate force and acceleration using these laws?

To calculate force, we use Newton's second law: force = mass x acceleration. This means that the force acting on an object will be equal to its mass multiplied by its acceleration. To calculate acceleration, we rearrange the equation to: acceleration = force/mass. This shows that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

5. Can these laws be broken or changed?

No, Newton's laws of motion are fundamental principles in physics and have been proven to hold true in countless experiments and observations. However, there are certain situations, such as in extreme speeds or at the subatomic level, where these laws may not accurately predict the behavior of objects. In these cases, more advanced theories, such as Einstein's theory of relativity, may be necessary to fully explain the phenomena.

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