Using g = 9.8 m/s2, the statement that best describes the roller coaster car when it is at the top of the loop-de-loop is that The car has both potential and kinetic energy, and it is moving at 24.6 m/s.
The correct answer is <span>B) The car has both potential and kinetic energy, and it is moving at 24.6 m/s.</span>
The mechanical work done by the sprinter during this time will be 4537.5 J , the average power the sprinter must generate will be 907.5 W and if the sprinter converts food energy to mechanical energy with an efficiency of 25% then he will be burning calories at 54.20 calories per second.
Work in physics is the energy that is transferred to or from an item when a force is applied along a displacement. It is frequently described in its most basic form as the result of force and displacement.
The quantity of energy moved or transformed per unit of time is known as power in physics. The watt, or one joule per second, is the unit of power in the International System of Units.. A scalar quantity is power.
Given 75-kg sprinter accelerates from rest to a speed of 11.0 m/s in 5.0 s.
So let,
m = 75 kg
v = 11.0 m/s
t = 5.0 s
So the mechanical work done by the sprinter during this time will be as follow:
W = 0.5 mv²
W = 0.5 (75)(11)²
W = 4537.5 J
The average power the sprinter must generate will be as follow:
Power(P) = W / t
P = 4537.5/5
P = 907.5 W
Only 25% is absorbed. So, the sprinter only absorbed 226.875 J per second which is equal to 54.20 calories per second.
Hence mechanical work done by the sprinter during this time will be 4537.5 J , the average power the sprinter must generate will be 907.5 W and if the sprinter converts food energy to mechanical energy with an efficiency of 25% then he will be burning calories at 54.20 calories per second.
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There water has a lot of salt in it, so it would be denser. People float better when the water is denser.
Answer:
The effect of lowering the condenser pressure on different parameters is explained below.
Explanation:
The simple ideal Rankine cycle is shown in figure.
Effect of lowering the condenser pressure on
(a). Pump work input :- By lowering the condenser pressure the pump work increased.
(b) Turbine work output :- By lowering the condenser pressure the turbine work increased.
(c). Heat supplied :- Heat supplied increases.
(d). Heat rejected :- The heat rejected may increased or decreased.
(e). Efficiency :- Cycle efficiency is increased.
(f). Moisture content at turbine exit :- Moisture content increases.
Answer:
and 
Explanation:
The wavelength of a visible light is 727.3 nm.
The formula is as follows :
f is the frequency of the visible light
Energy of a photon is given by :
E = hf, h is Planck's constant
Red color has a frequency of 
and energy per photon is 
.
