The person in Figure P4.55 weighs 170 lb. Each crutch makes an angle of 22.0 with the vertical (as seen from the front). Half of the persons weight is supported by the crutches, the other half by the vertical forces exerted by the ground on his feet. Assuming he is at rest and the force exerted by the ground on the crutches acts along the crutches, determine (a) the smallest possible coefficient of friction between crutches and ground and (b) the magnitude of the compression force supported by each crutch.

PH (111) Fall 2017 Practice for Test (1), Thursday September 7 th 1. Which of the following is a scalar quantity Speed, Velocity, Displacement, Acceleration, or none of them. 2. A certain physical quantity R is calculated using the formula: R = 4a² (b – c) where (a) is a speed and (b) and (c) are distances. What is the SI unit for R 3. Express the following statement as an algebraic expression: “There are 264 gallons in a one cubic meter container.” Let G represent the number of gallons and M represent the number of one cubic meter containers. 4. Gold can be compressed to a thickness of 1.0 micron to make gold leaf. If each cubic centimeter of gold has a mass of 19.32 g, what