A river has a steady speed of 0.500 m/s. A student swimsupstream a distance of 1.00 km and swims back to the startingpoint. If the student can swim at a speed of 1.20 m/s in stillwater, how long does the trip take? Compare this with the time thetrip would take if the water were still.

Slowing Down: The speed of an object moving through a viscous fluid is given by u (t) = A • e-bl(a) If the numerical value of A (in Sl units) is 8.40 and the numerical value of b (in Sl units) is 1.12. then what is the initial acceleration of the particle, at time + = 0?(b) How far does the particle move in the first 4.00 s?You may ignore gravity. The particle has the same density as the fluid.

Your friend wants to show off how quickly their car can accelerate. So you get in and they start driving. You notice that the pine tree scented air freshener that hangs from the rear view mirror makes an angle of 26.5 degrees with respect to the vertical (straight down) direction while the car is accelerating. Using this angle, you pull out your calculator and find the car's acceleration. The answer is:

A dolphin in an aquatic show jumps straight up out of the water at a velocity of 12.0 m/s. (a) List the knowns in this problem. (b) How high does his body rise above the water? To solve this part, first note that the final velocity is now a known and identify its value. Then identify the unknown, and discuss how you chose the appropriate equation to solve for it. After choosing the equation, show your steps in solving for the unknown, checking units, and discuss whether the answer is reasonable. (c) How long is the dolphin in the air? Neglect any effects due to his size or orientation.