Question

A yoyo of mass 2 kg and moment of inertia 0.04 kg m consists of two solid disks of radius 0.2 m, connected by a central spindle of radius 0.15 m and negligible mass. A light string is coiled around the central spindle. The yoyo is placed upright on a flat rough surface and the string is pulled with a horizontal force 22 N, and the yoyo rolls without slipping.

(a) What is the x-component of the acceleration of the center of mass of the yoyo? (in m/s )



unanswered

(b) What is the x-component of the friction force? (in N)

Answer 1

http://www.columbia.edu/~crg2133/Files/Physics/8_01/lotsOfProbs.pdf
Prob/ #29

Answer 2

Is not work for me, i tried but i don't know what im doing wrong

Answer 3

what is T in the equation a=... in Problem 29.. ?

I tried with cos(0) because there is no angle and T=22 N but it was wrong..

Answer 4

a=F(R+r)/(I/R+m*R)

Answer 5

above formula is incorrect, correct answer would be
a=8.25m/sec2

Answer 6

Do mention thanks once you get a green tick!!

Answer 7

1.83m/sec2 drop in comments which one is true acceleration??

Answer 8

and b thanks?

Answer 9

What is the correct forumla?

Answer 10

(a) Set up two equations. One for forces, one for torques.

For the first equation, which way does friction act? i.e. which way would the yoyo move if there was slip? Since there is no slip, friction must be acting *against* the intended direction of motion.

For the second equation, you have two forces acting at two radii, so two torques. Pick a direction (CW or CCW) and designate it as +ve (one makes more sense than the other).

Your first equation relates to the *linear* (translational) motion, in terms of the applied force, friction, the linear acceleration and mass.

Your second equation relates to the rotational motion, in terms of the torques, the moment of inertia, and the angular acceleration.

Put these together to eliminate friction.

You must also understand that because there is no slip (ie pure roll), the angular acceleration and the linear acceleration have a relationship.

This allows you to eliminate angular acceleration.

You are left with an expression for acceleration in terms of all the given values.

(b) Once you have worked out acceleration, just plug it into one of the two equations you found for part (a). One of these is much easier than the other :-)

Answer 11

juanpro
a=12.83333
f=2.333

Answer 12

excuse me
juanpro
a=12.83333
f=3.666

Answer 13

thanks a lot you save my life