2. pts) An athlete doing bench presses in the weight room (which a physicist wou

Question

2. pts) An athlete doing bench presses in the weight room (which a physicist would probably the mass room applies a force straight up that is just to lift a I15-kg barbell ar constant speed What is the athlete's Thought question Inorfor credir: How much work does the athlete rform during one lift? How much work does per gravity do on the barbell during the same lift h J. A 280 kg piano rests on the ground. You want to get it into the back of a moving truck I o meter above the ground. You do NOT need to show your work for this problem. Be sure ao inchude anirs and rese appropriate significant figures! a. i pt) How much force would you (and your friends) need to exert on the piano if you lift it straight up through 10 m at constant speed? pt. How much force would you need to exert on the piano to push it up 80 ramp to a final vertical height of 10 m at constant spend? (Your force is exerted parallel to the ramp.) e. (I pt) What is the mechanical advantage of using the ramp in part b. compared to lifting the piano straight up? d. (I pt.) How much work would you (and your friends) do on the piano lifting it straight up in pan Gay? e. I pt) How much work would you do on the piano by pushing it to the top of the ramp in part by? Thought question /nor for credirl: would you expect your answers to parts ed) & ee) to be equal or different? Ultimately, does having a large mechanical advantage" allow you to do less total work hence to expend less total energy) to perform a task? If not, then exactly what is the "advantage

Explanation / Answer

2.

the speed at which he is moving the barrel is

v=d/t=0.7/2.2=0.318 m/s

average power output of athlete is

P=FV=mgV=115*9.81*0.318

P=359 Watts

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