Question

X L Mertx final 2 Writt X Final 2 Writte total work dor force Drive%20-%20University%20of%20Denver/Freshman%20Year/Physics/Final/2012%20Written%20only%20(Fowler).pdf o megaf Fundamentals of Ph. Outlook d 3. (10 points) Consider the pulley system shown below, the pulley is frictionless and the string has negligible mass. Suppose there is nonzero kinetic friction between the mass m and the tabletop on which it slides. You apply with your hand a horizontal pulling force to the left and move the mass mover a displacement Ax at a constant speed. A) Write an expression for the total work done by this pulling force. B) Supposing that the masses are brought to rest after moving the distance Ar. They are the and mass m begins to slide to the right on the tabletop as mass Mmoves downward. Write an expression for their speed wafter moving that same distance Ar.

Answer 1

a) Let the pulling fence is F Since the mass m moves with constant speed, so the acceleration azo Free body diagrams FMHT TMR - Ving - Ving - F=T + WAR TEMO - Rang F = Ttang » F = mg tlx mg So, work done by this fonce to move a distance ox, WzFX AX = (mg+ux mg ) AX= (M+km) gax. by When the mass is released, (Accelentin a will be nonzero) PR sma Il nosaccelerat ma= T-MAR = Tolking ma= Mig-T 5 G = {m –Ukm)g (m+m) Im IT lik R VMQ Win alles traveling sx, Vn=uzas 12 am theme.or]