Several books are placed on a table. These books have a combined weight of 25 N and cover an area of 0.05 m2. How much pressure
1 answer:
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Answer:0 J
Explanation:
Given
For first step
change in internal Energy of the system is
Work done on the system
For second step
change in internal Energy of the system is
Work done on the system
Work done on the system is considered as Positive and vice-versa.
and from first law of thermodynamics
for first step
overall heat added
For overall Process Heat added is 0 J
at the lowest point in the trajector, the kinetic energy of the bob is 300 J.
Explanation:
The total mechanical energy of the bob at any point of its motion is given by
Where
is the kinetic energy, where
m is the mass of the bob
v is its speed
is the gravitational potential energy, where
g is the acceleration of gravity
h is the height of the bob, measured with respect to the lowest point of the trajector
In absence of friction, the total mechanical energy E remains constant. So we have:
- When the bob swings upward, the PE increases (because h increases) and the KE decreases (so the speed decreases). At the highest point in the trajector, the speed of the bob is zero (v=0), so its KE is also zero and all the mechanical energy is potential energy: U = 300 J
- When the bob swings downward, the PE decreases (because h decreases) and the KE increases (so the speed increases). At the lowest point in the trajectory, the height has become zero (h=0), so the PE is zero and all the mechanical energy is kinetic energy: KE = 300 J
Therefore, at the lowest point in the trajector, the kinetic energy of the bob is 300 J.
Learn more about kinetic energy:
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