# Thread: A vehicle travels a semi circular path of 48 metres radius

1. ## A vehicle travels a semi circular path of 48 metres radius

Hi All.

What do I need to know to solve this problem;

A vehicle is travelling a semi circular path of 48 metres radius in a time of 7 seconds, I am asked to find the velocity, speed, distance and displacement travelled?

any help appreciated

2. You need to know 3 things:

The formula for the circumference of a circle.

The difference between distance and displacement.

The difference between speed and velocity.

Hint: Think scalar vs. vector.

Does that get you started?

3. Hi Knowledge, you said;

You need to know 3 things:

The formula for the circumference of a circle.

The difference between distance and displacement.

The difference between speed and velocity.

Hint: Think scalar vs. vector.

Does that get you started?

I said. These I already know, what I don't know is how to include the time and work it out?

Sorry?

4. Well, if you know all of the above, then I don't see how you cannot understand where to include time and work out the solutions.

For example, velocity is a vector (includes both magnitude and direction) calculated by dividing the change in position (displacement) by the change in time:

$\displaystyle v=\frac{\Delta x}{\Delta t}$

5. Originally Posted by Knowledge
Well, if you know all of the above, then I don't see how you cannot understand where to include time and work out the solutions.

For example, velocity is a vector (includes both magnitude and direction) calculated by dividing the change in position (displacement) by the change in time:

$\displaystyle v=\frac{\Delta x}{\Delta t}$
Hi Knowledge, thanks for that info, my misunderstanding when reading the text books is whether my vehicle travelling round a semi-circle should be in Rad/s because the vehicle is going circler motion, or just m/s. I didn't know how to include the time because none of the examples i read included time in circler motion.

Although I know the difference between speed, velocity, distance and displacement, I miss the point where knowing these terms can work out the result of my question?

So I have c = 2 x pie x radius in my example = 301.6 metres around the circumference, then 301.6/7 = 43.1 m/s which is not necessarily Rad/s?