Sunday

December 21, 2014

December 21, 2014

Posted by **Susan** on Friday, December 3, 2010 at 2:00pm.

--------------------------------------------------------------------------------

(a) If the original length L of the rubber band is 1 m, by how much (in m) will it be stretched by the rotation?

Delta L = m

HELP: The centripetal force has to equal the elastic force.

HELP: The centripetal force is equal to

Fc = mass*length*omega2,

where length is now the stretched length, that is,

length = L + (Delta L).

The elastic force is equal to

Felast = k*(Delta L).

Since the two are equal, you have an equation for Delta L.

--------------------------------------------------------------------------------

(b) How much energy do you need to start the stone from rest and rotate as in part (a) with an angular speed of 9.2 rad/s? Neglect the mass of the rubber band.

Etotal = J

HELP: Add up the kinetic energy and the elastic potential energy.

HELP: Ekin = 1/2*m*v2, with v = length*omega.

Remember again to use the stretched length:

Eelast = 1/2*k*(Delta L)2

- Physics -
**Cynthia**, Sunday, December 5, 2010 at 2:01amm*(L+Delta L)*w^2=k*(Delta L)

Delta L=(m*w^2)/(k-m*w^2)

Mass: 156 g=.156kg

Answer: 0.128

**Answer this Question**

**Related Questions**

Physics - Rubber Band A 156 g hockey puck is attached to a rubber band and ...

Physics - I need help with part b... I found in part a that delta L is .29568m ...

Physics - A hockey puck slides along the ice. There is a frictional force ...

Physics - a person pushes on a hockey puck with their stick at an angle so the ...

Physics - A 0.18 kg point mass moving on a frictionless horizontal surface is ...

physics - Hockey Puck A 110 g hockey puck sent sliding over ice is stopped in 13...

Physics - 0.17 kg point mass moving on a frictionless horizontal surface is ...

physics - A hockey puck with mass 0.160kg is at rest on the horizontal, ...

physics - Unless otherwise stated, all objects are located near the Earth's ...

physics - a hockey puck is sliding across frictionless ice at 6m/s. a)what is ...