# Maths Question - Velocity

• June 23rd 2008, 01:34 AM
ForgottenMemorie
Maths Question - Velocity
Hello,

I would like some help please. I've spent alot of time going through different avenues but not succesfully.

A starting point would be appriciated, or correct equations to use please.

Question 1

http://i294.photobucket.com/albums/m...memorie/q1.jpg

My Thoughts : I dont even have a clue where to start with this one.

Question 2

http://i294.photobucket.com/albums/m...memorie/q2.jpg

-

My Thoughts : How is it possible to work out the velocity?

Velocity = Distance/Time

But the question does not have a figure for time, also is the distance 140m?

Acceleration = Velocity/Time

• June 23rd 2008, 03:50 AM
topsquark
Quote:

Originally Posted by ForgottenMemorie
Hello,

I would like some help please. I've spent alot of time going through different avenues but not succesfully.

A starting point would be appriciated, or correct equations to use please.

Question 1

My Thoughts : I dont even have a clue where to start with this one.

Well you already know the angular speed of the motor: it's 2000 rpm. So all you need to do is a unit conversion:
$\frac{2000~revolutions}{1~minute} \cdot \frac{2 \pi~rad}{1~revolution}$

To get the angular speed of the drum you know the gearbox is in a 200:1 ratio, so the angular speed of the drum would be....

What is the speed of the surface of the drum? That has to be the speed that the cable is coming in at. So
$v = r \omega$

-Dan
• June 23rd 2008, 03:52 AM
topsquark
Quote:

Originally Posted by ForgottenMemorie
Question 2
-

My Thoughts : How is it possible to work out the velocity?

Velocity = Distance/Time

But the question does not have a figure for time, also is the distance 140m?

Acceleration = Velocity/Time

Surely you know that
$F_c = \frac{mv^2}{r}$

You take it from here.

-Dan