a person with a femoral fracture lies in traction in order to to reset the healing bone. (a) based on the schematic, discuss qualitatively all of the places where friction acts in this system. (b) for the sake of this problem, pretend that the pulleys are replaced with fixed, smooth metal bars, and that the rope can slide around them with coefficient of static friction μ = 0.02. assuming a reasonable value for w and using other visual clues from the diagram, estimate the total vector force transmitted to the knee assuming (i) impending motion of the weight upward and (ii) impending motion of the weight downward?

Describe the path of the electric current through a circuit?

The frequency of vibrations of a vibrating violin string is given by f = 1 2l t ρ where l is the length of the string, t is its tension, and ρ is its linear density.† (a) find the rate of change of the frequency with respect to the following. (i) the length (when t and ρ are constant) (ii) the tension (when l and ρ are constant) (iii) the linear density (when l and t are constant) (b) the pitch of a note (how high or low the note sounds) is determined by the frequency f. (the higher the frequency, the higher the pitch.) use the signs of the derivatives in part (a) to determine what happens to the pitch of a note for the following. (i) when the effective length of a string is decreased by placing a finger on the string so a shorter portion of the string vibrates df dl 0 and l is ⇒ f is ⇒ (ii) when the tension is increased by turning a tuning peg df dt 0 and t is ⇒ f is ⇒ (iii) when the linear density is increased by switching to another string df dρ 0 and ρ is ⇒ f is ⇒

Polly is pushing a box across the floor with a force of 30 n. the force of gravity is –8 n, and the normal force is 8 n. which value could describe the force of friction if polly could not move the box?