Small block on a track - Finding Normal forces and....

nukeman

1. The problem statement, all variables and given/known data

Here is the question. Can someone please help, since I missed the section of class that went over this, any my textbook does not cover this well. Look below at question 1, a) and b)





2. Relevant equations



3. The attempt at a solution

grzz

Which are the forces at point Q?

nukeman

At point Q - Forces are Gravity down... Does it have tangential and radial?

grzz

The block is touching the track. Hence besides the weight there is also the ...

nukeman

Force of gravity and the normal force

grzz

Correct.
Now for a mass to perform circular motion, it needs a ...

nukeman

Force?

grzz

What do we call this particular force?

nukeman

I am not sure. Momentum force?

grzz

Any mass performing circular motion needs a force towards the centre of the circle. This particular force is called ...

nukeman

Centripetal Force?

grzz

CORRECT.

what is the formula for this centripetal force in terms of the speed at Q?

nukeman

I am not sure on that... I cant find it in my book (awfull book). :(

?

grzz

This forum is for helping and not for doing the work for you.
Try looking up 'centripeta force' on internet search engine. That is the way to learn.

nukeman

Did not mean to imply that.

F = MAc = MV^2/r

Is that it? what is the c ?

grzz

It is ok. You are welcome to this forum!

You got the right formula.
A - acceleration, c- centripetal.

Now try to find the speed at point Q.

nukeman

This is where i have trouble.

When i plug everything in:

F = (.100)(2.00)^2 / (.150)

I get 2.66 ?