Any Help is appriciated: 3 - Kinematic Problems

  • Thread starter naren11
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In summary, the person is asking for help with the last three questions from their physics problem set. They explain that they are taking a distance education course and don't have friends to help them. They provide links to images of the questions and ask for as much help as possible. They also provide equations and ask for help with questions 13, 14, and 15.
  • #1
naren11
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Hello,

Sorry about this and please don't think I m a lazy guy who is posting an assinment that is due tomorrow. I m scanning it and posting this because these questions do not involve numbers but require reasoning in which i m bad at. I m currenly taking a Physics 2nd year distance ed course so i don't really have friends to help me with these questions. So considering u guys as my friends I post the last 3 questions from my problem set.

1st & 2nd Question:

http://img125.exs.cx/img125/4971/lastscan1bv.jpg

3rd Question

http://img201.exs.cx/img201/4290/lastscan27cv.jpg

Plz answer much as possible. I m preparing for my finals and these questions are recommended for me through my tutor. Thank you very much! I will ck the forums couple of hours later :smile:
 
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  • #2
From the diagram [1] [tex]ma = mg - T[/tex]

[tex]\tau = RT = I\alpha[/tex]

[tex]\alpha = \frac{RT}{I}[/tex]

We also know that [2] [tex]\alpha = \frac{a}{R}[/tex] so

[3] [tex]a = \frac{R^2T}{I}[/tex]

from [1] [tex]a = g - \frac{T}{m}[/tex]

substitute [3] [tex]\frac{R^2T}{I} = g - \frac{T}{m}[/tex]

[tex]T = \frac{g}{\frac{R^2}{I}+\frac{1}{m}}[/tex] = [tex]\frac{Img}{mR^2+I}[/tex] [4]

Divide the top and bottom of [4] by I to get the equation for 13 (c)

Substitute [4] into [3] [tex]a = \frac{R^2mg}{mR^2+I}[/tex]

divide this by [tex]R^2m[/tex] to get the

equation for 13 (b)

Substitute (b) into [2] to get the equation for 13 (a)

For question 14, You just need to use conservation of energy and rearrange for v.

For question 15, all you need to know is that

[tex]\alpha = \frac{\tau}{I}[/tex] and the expressions for I for the rod and masses.
 
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  • #3


Hello,

First of all, don't worry about asking for help. It shows that you are taking your studies seriously and are willing to put in the effort to understand the material. That is something to be proud of.

Now, onto the questions. The first two questions seem to be related to projectile motion. In order to solve these problems, you will need to use the equations of motion for projectile motion, which are:

- Vertical displacement (y) = initial vertical velocity (Voy) x time (t) + 1/2 x acceleration due to gravity (g) x time squared (t^2)
- Horizontal displacement (x) = initial horizontal velocity (Vox) x time (t)
- Vertical velocity (Vy) = initial vertical velocity (Voy) + acceleration due to gravity (g) x time (t)
- Horizontal velocity (Vx) = initial horizontal velocity (Vox)

In the first question, you are given the initial velocity (Voy) and the angle at which the object is launched (theta). You will need to use trigonometry to find the horizontal and vertical components of the initial velocity (Vox and Voy). Then, you can use the equations of motion to find the vertical displacement (y) and horizontal displacement (x) at a given time (t).

In the second question, you are given the horizontal displacement (x) and the angle at which the object is launched (theta). Again, you will need to use trigonometry to find the horizontal and vertical components of the initial velocity (Vox and Voy). Then, you can use the equations of motion to find the vertical displacement (y) and the time (t) at which the object reaches the given horizontal displacement (x).

For the third question, you will need to use the equation for centripetal force, which is Fc = (mass x velocity^2) / radius. In this case, the force is provided (400 N) and you are given the mass of the object and the radius of the circular path. You can rearrange the equation to solve for the velocity (v) and then use that velocity to find the period (T) of the motion, which is the time it takes for the object to complete one full revolution.

I hope this helps. Just remember to break down the problems into smaller steps and use the appropriate equations. Don't hesitate to ask for clarification if needed. Good luck on
 

FAQ: Any Help is appriciated: 3 - Kinematic Problems

What are kinematic problems?

Kinematic problems involve the study of motion without considering the forces that cause the motion. This includes the analysis of displacement, velocity, and acceleration of an object.

How do you solve kinematic problems?

To solve kinematic problems, you need to identify the given information and the unknown quantity you are trying to find. Then, use the appropriate kinematic equations to solve for the unknown quantity.

What are the three kinematic equations?

The three kinematic equations are:

  • Displacement (Δx) = Initial velocity (v0) x Time (t) + 1/2 x Acceleration (a) x Time (t)2
  • Final velocity (v) = Initial velocity (v0) + Acceleration (a) x Time (t)
  • Displacement (Δx) = (Initial velocity (v0) + Final velocity (v))/2 x Time (t)

What are some common units used in kinematic problems?

The most common units used in kinematic problems are meters (m) for displacement and acceleration, meters per second (m/s) for velocity, and seconds (s) for time.

Can kinematic problems be applied to real-world situations?

Yes, kinematic problems can be used to analyze and understand the motion of objects in real-world situations. For example, they can be used to calculate the speed and distance of a car in motion or the acceleration of a falling object due to gravity.

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