Friday

March 27, 2015

March 27, 2015

Posted by **mariel** on Friday, December 3, 2010 at 2:41am.

- physics -
**drwls**, Friday, December 3, 2010 at 5:59amYou will need to calculate the moment of inertia of the spool, which is

I = (1/2)M R^2 = (0.5)(0.5 kg)(.075m)^2

= 1.406*10^-3 kg m^2

The mass m on a string applies a torque of

T = m g R = 5*9.8*.075 = 3.675 N-m

(a) Angular acceleration of the spool is

(alpha) = T/I

Compute the number, in radians/s^2

(b) The angle rotated through when the string is fully unwound is

theta = L/(2 pi R)

The time t to unwind is given by

theta = (1/2)*(alpha)*T^2

Solve for T and then compute the angular velocity at that time:

w = alpha*T

**Answer this Question**

**Related Questions**

Physics - A string is wound around a solid cylindrical spool of mass 9.7 kg and ...

Physics - Use conservation of energy to determine the angular speed of the spool...

physcs - A string is wrapped around a uniform solid cylinder of radius 3.10 cm, ...

physics - A 4.00-m length of light nylon cord is wound around a uniform ...

Physics - Red ribbon wound around a red spool (above) is taped to blue ribbon ...

phy - Review. An object with a mass of m 5 5.10 kg is attached to the free end ...

physics - A string is wrapped around a uniform disk of mass M = 1.6 kg and ...

Physics - A 90kg stuntman falls from a building that is 80 meters tall. (Vo = 0)...

physics - A 90kg stuntman falls from a building that is 80 meters tall. (Vo = 0...

Physics - A freely hanging block of mass 5 kg is attached to a massless string ...