Answer:
Explanation:
Assuming no energy lost, according to the law of conservation of energy, the kinetic energy of the automobile becomes potential energy after the crash:
Here m is the automobile's mass, v is the speed of the car before impact, k is the "bumper" constant and x is the compression of the bumper due to the collision. Solving for v:
Answer:
The wire now has less (the half resistance) than before.
Explanation:
The resistance in a wire is calculated as:
Were:
R is resistance
is the resistance coefficient
l is the length of the material
s is the area of the transversal wire, in the case of wire will be circular area ().
So if the lenght and radius are doubled, the equation goes as follows:
So finally because the circular area is a square function, the resulting equation is half of the one before.
Answer:
a) h = 53.8 m, b) h_minimum = 28 m, h_maximum = 63.3 m
Explanation:
a) For this exercise let's use Bernoulli's equation.
The subscript 1 is for the tank and the subscript for the building
P₁ + ½ ρ g v₁² + ρ g y₁ = P₂ + ½ ρ g v₂² + ρ g y₂
In general, the water tanks are open to the atmosphere, so P1 = Patm, also the tanks are very large so the speed of the water surface is very small v₁=0 and as they give us the precious static, this it is when the keys are closed so the output velocity is zero, v₂= 0. The height of the floors in a building is y₂ = 12 m
we substitute in Bernoulli's equation
P_{atm} + 0 + ρ g h = P₂ + 0 + ρ g y₂
h =
h = + y₂
indicate that the value of ΔP = 410 10³ Pa
we calculate
h = 410 10³ / (1000 9.8) + 12
h = 53.8 m
b) ask for the height range for the minimum and maximum pressure
h = ΔP / rho g
minimum
h_minimum = 275 103/1000 9.8
h_minimum = 28 m
maximums
h_maximo = 620 103/1000 9.8
h_maximum = 63.3 m