How much work is done when a porcelain vase with mass of 2.5 kg is lifted up 3 m to a shelf? (HINT- Weight can be used as Force
1 answer:
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Answer:
Explanation:
Given
Cross-sectional area of wire
Extension of wire
Extension in a wire is given by
where,
for same force, length and material
Divide (i) and (ii)
Answer:
a) 0.28 m or 28 cm is the minimum height above ground the fish reaches.
b) at the height of 0.484 m height , the pufferfish will eventually come to rest.
c) There exists two types of energy remain at the equilibrium point in the system. These are :
Gravitational potential energy = 23.72J
Spring potential energy = 0.384 J
Explanation:
Given that :
Mass of the pufferfish m =5kg
initial height of the fish h =5.5m
length of the spring l =0.5m
Spring constant K =3000N/m
a)
Assuming no energy loss to friction, what is the minimum height above the ground that the pufferfish reaches?
Lets assume that the minimum height the fish reaches is = x meters
Now by using the conservation of energy; we realize that :
Initial total energy = final total energy
Gravitational potential energy =
Gravitational potential energy' + Spring potential energy (kinetic energy is zero in both cases)
Replacing our given values into the above equation; we have :
269.5 = 47.5 x + 1500(0.5 -x )²
269.5 = 47.5 x + 1500(0.25 - x²)
269.5 = 47.5 x + 375 - 1500 x²
269.5 - 375 = 47.5 x - 1500 x²
-105.5 = 47.5 x - 1500 x²
-105.5 + 1500 x² - 47.5 x = 0
1500 x² - 47.5 x - 105.5 = 0
By using quadratic equation and taking the positive value;
x = 0.28 m or 28 cm is the minimum height above ground the fish reaches.
b)
At the equilibrium position the weight of fish will be equal to the force applied by the spring thus
mg = kx
substituting our given values ; we have:
(5)(9.8) = 3000x
x = 61.22
x = 0.016m : so this is the compression in the spring
Now; to determine the height the pufferfish gets to before it eventually come to rest; we have
(0.5-0.016) m = 0.484m
therefore, at the height of 0.484 m height , the pufferfish will eventually come to rest.
c)
There exists two types of energy remain at the equilibrium point in the system. These are :
Gravitational potential energy = mgh' = (5)(9.8)(0.484)
= 23.72J
and spring potential energy
To find the temperature it is necessary to use the expression and concepts related to the ideal gas law.
Mathematically it can be defined as
Where
P = Pressure
V = Volume
n = Number of moles
R = Gas constant
T = Temperature
When the number of moles and volume is constant then the expression can be written as
Or in practical terms for this exercise depending on the final temperature:
Our values are given as
Replacing
Therefore the final temperature of the gas is 800K