Reasoning problems on kinematics without numbers

[naren11]

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

 

[asrodan]

From the diagram [1] $$ma = mg - T$$

$$\tau = RT = I\alpha$$

$$\alpha = \frac{RT}{I}$$

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

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

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

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

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

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

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

divide this by $$R^2m$$ 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

$$\alpha = \frac{\tau}{I}$$ and the expressions for I for the rod and masses.

 

[thepatientmental]

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