# Beginner's mechanics problem

• radagast_
In summary, the conversation discusses a physics problem involving a contraption with two masses, m and M, on an incline. The goal is to find the angle phi. The conversation includes hints and suggestions for solving the problem, such as analyzing forces and applying Newton's laws. The person seeking help expresses their progress and asks for further guidance.

#### radagast_

Hello.
I have the attached problem.
The body whose mass is m doesn't move relative to the body M. Them both are affected only by gravity.
I need to find the angle phi.

Can anyone please help me?

http://img135.imageshack.us/img135/4690/1113169793tx6.gif" [Broken]

Thank you.

Last edited by a moderator:
Show us what you've done so far and point out where you got stuck.

Hint: What's the motion of that contraption along the incline?

Doc Al said:
Show us what you've done so far and point out where you got stuck.

Hint: What's the motion of that contraption along the incline?

well, I tried to draw the forces on the little mass m, and I know the whole contraption is under a force (mgsin(alpha)), and I got to the point that on the little mass, I have the tension and the mg force and a d'elambert force to the left.
Im kinda stuck on doing that on the whole thing. I don't really know how to relate to the little mass in reference with the M mass, ie - I want to write the motion equations from the accelerating contraptions' POV, but then I don't know how to take the m mass's forces (should I take it as another force, ie mg+Mg=mgsinalpha, or not...).

D'alembertian forces? Let's have none of that crazy talk!

What's the acceleration of the contraption (and thus mass m)? Analyze forces parallel and perpendicular to the incline and apply good old Newton.

Thanks.
I think I got it... I'll try it and see how it turns out
:)

## 1. What is the definition of mechanics?

Mechanics is a branch of physics that deals with the study of motion, forces, and energy.

## 2. What is the difference between kinematics and dynamics?

Kinematics is the study of motion without considering its causes, while dynamics is the study of motion taking into account the forces that cause it.

## 3. How do I solve a beginner's mechanics problem?

First, identify all the given information and what you are trying to solve for. Then, apply the appropriate equations and principles of mechanics to find the solution. It is important to draw a clear and labeled diagram to help visualize the problem.

## 4. What are the common units used in mechanics?

The common units used in mechanics are meters (m) for distance, kilograms (kg) for mass, and seconds (s) for time. Other commonly used units include newtons (N) for force, joules (J) for energy, and meters per second (m/s) for velocity.

## 5. Can you provide some tips for improving problem-solving skills in mechanics?

Some tips for improving problem-solving skills in mechanics include practicing with a variety of problems, breaking down complex problems into smaller parts, and making sure to fully understand the basic principles and equations of mechanics. It can also be helpful to work with a study group or consult with a teacher or tutor for extra support.

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