Fossil fuels are an important natural resource used by society. which of the following best describes fossil fuels? a. they are any liquid fuel derived from once-living matter. b. they are organic fuels derived from ancient plants and animals. c. they are fuels in which dinosaur fossils are commonly found. d. they are naturally occurring inorganic fuels like coal and petroleum.

Asilver dollar is dropped from the top of a building that is 1324 feet tall. use the position function below for free-falling objects. s(t) = −16t2 + v0t + s0 (a) determine the position and velocity functions for the coin. s(t) = v(t) = (b) determine the average velocity on the interval [1, 2]. ft/s (c) find the instantaneous velocities when t = 1 second and t = 2 seconds. v(1) = ft/s v(2) = ft/s (d) find the time required for the coin to reach the ground level. (round your answer to three decimal places.) t = s (e) find the velocity of the coin at impact. (round your answer to three decimal places.) ft/s

A55-kg pilot flies a jet trainer in a half vertical loop of 1200-m radius so that the speed of the trainer decreases at a constant rate. knowing that the plane has a speed of 550 km/h at point a, and the pilot experiences weightlessness at point c (i.e., the normal force from the seat bottom is zero), determine (a) the deceleration of the plane, (b) the force exerted on her by the seat of the trainer when the trainer is at point b.

Auniform bridge, 20 m long and weighing 40000 n is supported by two pillars located 3.0 m from each end. if a 19600 n car is parked 8.0 m from one end of the bridge, how much force does each pillar exert?