Answer:
128379.69 J
Explanation:
Potential energy: This can be defined as the energy of a body to to position in the gravitational field. The S.I unit of potential energy is Joules (J).
The expression for potential energy is given as,
ΔEp = mgΔH
ΔEp = mg(H₂-H₁)..................... Equation 1
Where ΔEp =change in Potential Energy, m = mass of the man, g = acceleration due to gravity, H₂ = Height of the 37th floor, H₁ = height of the first floor
Given:m = 91.2 kg, g = 9.8 m/s², H₁ = 3.99 m, H₂ = 3.99×37 = 147.63 m.
Substitute into equation 1
ΔEp = 91.2(9.8)(147.63-3.99)
ΔEp = 893.76(143.64)
ΔEp = 128379.69 J.
Answer:
a)η = 0.088
b) η = 0.5
Explanation:
a) The attached figure shows the P-V diagram for the process described in the exercise. According to that figure, the work during process 1-2 is equal to:
W(1-2) = -n*R*T1*ln(vi/vf) = -n*R*T1*ln(V/(V/2)) = -n*R*T1*ln(2)
the work during process 2-3 is equal to:
W(2-3) = nR*(T2-T1)
The work done during the 3-1 process equals zero, because the volume is constant. The specific heat for the molar specific heat equals:
cp = 7*R/2, where R is gas constant.
Qin = n*cp*(T2-T1) = 7*n*R/2*(T2-T1)
the efficiency of the cycle is equal to:
η = (W(1-2) + W(2,3))/Qin = (-n*R*T1*ln2 + n*R*(T2-T1))/(7*n*R/2*(T2-T1) = (2/7)*(1-(ln2/((T2/T1)-1)))
if we write the expression between volume and temperature, we have:
T2/T1 = v1/v2
T2/T1 = v/(v/2))
T2/T1 = 2
η = (2/7)*(1-(ln2/(2-1))) = 0.088
b)
The equation for efficiency of Carnot will be equal to:
η = 1-(T1/T2) = 1 - (1/2) = 0.5
Explanation:
A race car's main target is how to have rapid acceleration by scaling its speed. Acceleration of car is mostly a product of the force of the car engine.
According the newtons second law"The acceleration of body in motion depends on two main variables, the net force acting on it and the mass".
It is also written mathematically as:
F = m x a
F is the net force produced by the engine
m is the mass of the car
a is the acceleration.
Re-writing the equation:
Now Acceleration =
We can see that acceleration is directly related to increasing force but inversely proportional to the mass.
A race car needs to have a good acceleration so as to attain top speed.
The more the mass, the less the acceleration.
This is why extra weight like the seats are expunged.
learn more:
Newton's laws brainly.com/question/11411375
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Answer:
Explanation:
In a LC circuit The time constant τ is the time necessary for 60% of the total current (maximum current), pass through the inductor after a direct voltage source has been connected to it. The time constant can be calculated as follows:
Therefore, the time needed for the current to reach a fraction f = 0.6(60%) of its maximum value is: