A14.0 m uniform ladder weighing 490 n rests against a frictionless wall. the ladder makes a 63.0°-angle with the horizontal.
(a) find the horizontal and vertical forces (in n) the ground exerts on the base of the ladder when an 820-n firefighter has climbed 3.80 m along the ladder from the bottom. (horizontal force, vertical force)
(b) if the ladder is just on the verge of slipping when the firefighter is 9.10 m from the bottom, what is the coefficient of static friction between ladder and ground?
(c) what if? if oil is spilled on the ground, causing the coefficient of static friction to drop to half the value found in part (b), what is the maximum distance (in m) the firefighter can climb along the ladder from the bottom before the ladder slips?

Classify the following soils according to the uscs classification system. provide appropriate uscs designations. a) this sample of well-graded gravel with sand was obtained from a large earthen dam in vancouver, canada. the sample has 73% fine to coarse sub-angular gravel, 25% fine to coarse sub-angular sand and 2% fines. the maximum size of the particles is 75 mm. the coefficient of curvature is 2.7, while the uniformity coefficient is 12.4. b) this dark brown and wet soil with a “strong organic odor” has 100% passing the no. 200 sieve. the liquid limit of the material is 32% when not dried and is 21% when oven-dried. the plastic index is 21% when not dried. c) this sand has 61% predominantly fine sand, 23% silty fines, and 16% fine sub-rounded gravel size. the maximum size is 20 mm. the liquid limit is 33% and the plastic limit is 27%. d) this soil has 74% fine to coarse sub-angular reddish sand and 26% organic and silty dark brown fines. the liquid limit is 37% when not dried and is 26% when oven dried. the plastic index is 6% when not dried.

What is meant by the statement" the melting poin of glycerine is 13 degree celsius

The power exerted by a muscle is the product of the force exerted and the velocity of contraction. the area of which of these shaded regions represents the power exerted while a weight is lifted at maximum speed?