Apparently the myth is simply not true. A penny just can't gather enough velocity from the top of the Empire State Building to do any real harm. Footage was proved by "Mythbusters", which airs on The Science Channel.
Since the system itself is giving off heat, this is a
reduction in the internal energy.
heat = - 25,000 J
Since work is being done on the system, therefore it is
an additional energy to the system. Work is given as:
work = - P dV
work = - 1.50 atm (6 L – 12 L)
work = 9 L atm
Since it is given that 1 L atm is equivalent to 101.3 J,
therefore the total energy added is:
energy due to work = 9 L atm (101.3 J / 1 L atm)
energy due to work = 911.7 J
Therefore the total change in internal energy is the sum
of heat and energy due to work:
Change in internal energy = - 25,000 J + 911.7 J
Change in internal energy = - 24,088.3 J
<span>Therefore, approximately 24.1 kJ of energy is lost by the
system in the total process.</span>
<span>
</span>
<span>Answer:</span>
<span>-24.1 kJ</span>
Complete Question
The complete question is shown on the first uploaded image
Answer:
the change in energy of the block due to friction is ![E = -126 \ J](https://tex.z-dn.net/?f=E%20%3D%20-126%20%5C%20J)
Explanation:
From the question we are told that
The frictional force is ![F_f = 21 \ N](https://tex.z-dn.net/?f=F_f%20%20%3D%20%2021%20%5C%20N)
The mass of the block is ![m_b = 8 \ kg](https://tex.z-dn.net/?f=m_b%20%20%3D%208%20%5C%20kg)
The length of the ramp is ![l = 6 \ m](https://tex.z-dn.net/?f=l%20%3D%20%206%20%5C%20m)
The height of the block is ![h = 2 \ m](https://tex.z-dn.net/?f=h%20%3D%202%20%5C%20m)
The change in energy of the block due to friction is mathematically represented as
![\Delta E = - F_s * l](https://tex.z-dn.net/?f=%5CDelta%20E%20%20%3D%20%20-%20F_s%20%20%2A%20l)
The negative sign is to show that the frictional force is acting against the direction of the block movement
Now substituting values
![\Delta E = -(21)* 6](https://tex.z-dn.net/?f=%5CDelta%20E%20%20%3D%20%20-%2821%29%2A%20%206)
![\Delta E = -126 \ J](https://tex.z-dn.net/?f=%5CDelta%20E%20%3D%20-126%20%5C%20J)