Problem #2. For the free-falling parachutist with linear drag, assume a first jumper is 70 kg and has a drag coefficient of 12 kg/s. If a second jumper has a drag coefficient of 15 kg/s and a mass of 75 kg, how long will it take him to reach the same velocity the first jumper reached in 10 s?

Many birds can attain very high speeds when diving. Using radar, scientists measured the altitude of a barn swallow in a vertical dive; it dropped 208 m in 3.0 s. The mass of the swallow was estimated to be 0.018 kg, and its cross-section area as 5.6 x 10-4 m2. What was the drag coefficient for this swallow as it dove?

A person catches a ball with a mass of 145 g dropped from a height of 60.0 m above his glove. His hand stops the ball in 0.0100 s. What is the force exerted by his glove on the ball? Assume the ball slows down with constant acceleration.

What is the mass of the box?

While rollerblading through your neighborhood, you suddenly lose control and begin coasting down a hill, unable to stop. Fortunately, you see a neighbor moving a mattress into their house and decide that colliding with the mattress would be far less painful than the alternatives. Your plan works to perfection and you are slowed gently over the course of 1.4 seconds. Assuming your mass is 80 kg and your initial velocity was 10 m/s, find the average force applied on your body by the mattress (in N).

Dr. Miller is conducting an experiment. He has a stack of books on a table which is frictionless and flat. He applies a force F on the stack, and finds that it accelerates at 3.0 m/s². He then adds a book to the stack. This is a physics textbook that has a mass of 1.0 kg. He then applies the same force F on the stack and finds that now the stack accelerates at 2.0 m/s². What was the mass of the original stack of books? a) 1.0 kg Ob) 2.0 kg c) 3.0 kg O d) none of the above

A semi is traveling down the highway at a velocity of v = 27.5 m/s. The driver observes a wreck ahead, locks his brakes, and begins to slide. The truck has mass m and a coefficient of kinetic friction between the tires and the road of μk = 0.16. Write an expression for the sum of the forces in the x-direction for the truck while braking? Using the results from Part (a), input an expression for the truck's acceleration, at, while breaking? What is the magnitude of the acceleration in m/s2?  How far does the truck travel, d in meters, before stopping?

An ice hockey puck is sliding over a frictionless horizontal surface with a constant velocity of vo = 10.2 m/s. Find the velocity of the puck after it passes a rough area of length L 6 m and with the kinetic friction coefficient u = 0.33 as shown below. Hint: the mass of the puck is not needed, you can either calculate everything per unit of mass or, if it helps, take m 160 grams. %3D %3D %3D %3D m Vo L The steps to follow: (1) find the initial KE of the puck; (2) find the work done by the friction force (should be negative); (3) find the final kinetic energy as KE; = KE; + W, meaning that some of the initial kinetic energy is lost due to the work done by friction; (4) from the final KE find the final speed. The final speed of the puck, Vf =7.28 X Units m/s %3D If the initial speed of the puck is not high enough the puck will get stuck in the rough area. At what minimal initial speed should the puck move to barely make it through the rough area? The minimal initial velocity, Vmin =…

Air track: two objects tied together by a string. The figure shows a glider with mass my that moves on a level, frictionless air track in a physics lab. It is connected by a string passing over a small frictionless pulley to a hanging weight with total mass m₂. The string is light and flexible, and it doesn't stretch. (a) Find the acceleration of each object and the tension in the string. (b) What happens to the acceleration when m, is two times heavier than that of m₂? (c) Now my is four times heavier than that of m₂. Calculate the distance between it traveled during the initial period of two (2) seconds after the glider started moving. The tract is long enough for the travel. Show your work that leads to your answer. Explain each step in your work to explanation -quation WILIT T