20 A measure of the speed and direction of an object's motion
1 answer:
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Answer:
The acceleration of the train is 5 m/s².
Explanation:
Given:
let the initial velocity of a train = 5 m/s and
final velocity of a train = 45 m/s
time taken = 8 s
To find:
acceleration: ?
Solution:
We define acceleration as change in velocity per unit time that is the difference between the final velocity and initial velocity divided by time.
On substituting the above values we get the required acceleration
Therefore,the acceleration of the train is 5 m/s².
Answer: The formula used to solve the problems related to first law of thermodynamics is
Explanation:
First law of thermodynamics states that the total energy of the system remains conserved. Energy can neither be destroyed, nor be created but it can only be transformed into one form to another.
Its implication is any change in the internal energy will be either due to heat energy or work energy.
Mathematically,
where, Q = heat energy
W = work energy
= Change in internal energy
Sign convention for these energies:
For Q: Heat absorbed will be positive and heat released will be negative.
For W: Work done by the system is negative and work done on the system is positive.
For : When negative, internal energy is decreasing and when positive, internal energy is increasing.
Hence, the formula used to solve the problems related to first law of thermodynamics is