Aforce platform is a tool used to analyze the performance of athletes measuring the vertical force that the athlete exerts on the ground as a function of time. starting from rest, a 67.0-kg athlete jumps down onto the platform from a height of 0.720 m. while she is in contact with the platform during the time interval 0 < t < 0.800 s, the force she exerts on it is described by the function
f = 9 200t − 11 500t2
where f is in newtons and t is in seconds.
(a) what impulse did the athlete receive from the platform?
n · s up

(b) with what speed did she reach the platform?
m/s

(c) with what speed did she leave it?

(d) to what height did she jump upon leaving the platform?

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.

Which of the following is the phase that results when the moon is on the opposite side of the earth from the sun? a. quarter moon b. crescent moon c. new moon d. full moon

Which one of the following terms is used to indicate the natural tendency of an object to remain at rest or in motion at a constant speed along a straight line? velocity acceleration equilibrium force inertia