The summit of Mount Everest is 8850 m above sea level. (a) How much energy would a 90 kg climber expand against the gravitational force on him in climbing to the summit from sea level? (b) How many candy bars, at 1.25 MJ per bar, would supply an energy equivalent to this? Your answer should suggest that work done against the gravitational force is a very small part of the energy expended in climbing a mountain.
The mass of the climber is, m = 90 kg
The energy that the climber gets per bar, E = 1.25 MJ
The height of the summit of Mount Everest, h = 8850 m
The acceleration due to gravity is,
The energy of the climber against the gravitational force from the sea level shows the results that there is a change in potential energy.
Change in potential energy, (1)
The work or energy expanded by the climber to go against the gravitational force to climb to the summit of the mountain is given using equation (1):
W = Change in potential energy
Hence, the value of the energy is .
The number of candy bars that are required by the climber to supply energy is given as:
Hence, the required candies are 6 bar .
An outfielder throws a baseball with an initial speed of 81.8 mi/h . Just before an infielder catches the ball at the same level, the ball’s speed is 110 ft/s . In foot-pounds, by how much is the mechanical energy of the ball–Earth system reduced because of air drag? (The weight of a baseball is 9.0 oz )
A volcanic ash flow is moving across horizontal ground when it encounters a upslope. The front of the flow then travels 920 m up the slope before stopping. Assume that the gases entrapped in the flow lift the flow and thus make the frictional force from the ground negligible; assume also that the mechanical energy of the front of the flow is conserved. What was the initial speed of the front of the flow?
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