1. Mar 4, 2012

scruffles

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

The black curve represents the position of a spot on the x-axis projection of a spinning wheel.

a) Which curve represents the velocity of that spot? blue
b) What is the angular speed of the wheel?
c) What is the tangential speed of the wheel, assuming the full radius of the wheel is represented in this projection.
d) Does the x-projection have an angular acceleration at any time on the graph? Explain.

3. The attempt at a solution

I have no idea how to read this graph. The only thing I can guess is that a) would be the blue line? Please help!
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Mar 5, 2012

tiny-tim

welcome to pf!

hi scruffles! welcome to pf!
(a) correct
(b) hint: how long does it take to go round 360° ?
(c) hint: how far does it go when it goes round 360° ?
(d) sorry, i don't understand the question

3. Mar 5, 2012

scruffles

So for b) would the angular speed would be .4s?
c) would it be 0? since it goes from -8 to 8 ?

4. Mar 5, 2012

tiny-tim

b) yes

c) no (how much tape would you have to wind round the wheel?)

5. Mar 5, 2012

scruffles

would i use C=2pir?
c= 2(3.14)(5) = 31.4 cm?

6. Mar 5, 2012

why 5 ?

7. Mar 5, 2012

scruffles

because the diameter of the wheel is 10? so half of it would be the radius of 5?

8. Mar 5, 2012

tiny-tim

but the graph shows x going from -10 to 10, so half of that would be 10 ?

9. Mar 5, 2012

scruffles

you're right, my mistake. Thanks for your help!