15. [-/1 Points] DETAILS SERCP11 S.A.P.074. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A student evaluates a weight loss program by calculating the number of times he would need to climb a 15.0 m high ight of steps in order to lose one pound (0.45 kg) of fat. Metabolizing 1.00 kg of fat can release 3.77 x 107 J ofchemical energy and the body can convert about 18.8% of this into mechanical energy (the rest goes into internal energy.) HINT (a) How much mechanical energy (in J) can the body produce from 0.450 kg of fat? |:|J (b) How many trips up the flight of steps are required for the 64.0 kg student to lose 0.450 kg of fat? Ignore the relatively small amount of energy required to return down the stairs. Need new m M 16. [0\" Points] DETAiLS PREVIOUS ANSWERS SERCP11 5.A.P.D78. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A hummingbird hovers by exerting a downward force on the air equal, on average, to its weight. By Newton's third law, the air exerts an upward force of the same magnitude on the bird's wings. Find the average mechanical power (in W) delivered by a 3.20 g hummingbird while hovering if its wings beat 50.0 times per second through a stroke 3.42 cm long. HINT 0.0004 x w Now How m m