Two air craft P and Q are flying at the same speed 300m/s. The direction along which P is flying is at right angles to the direc
1 answer:
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Answer:
The wave speed is calculated below:
Explanation:
Given,
number of waves passed per minute = 8
time period = 1 minute = 60 s
distance between successive wave crests = 20 m
waves passing interval per second =
Now,
wave speed = 20 m ×
= m/s
= 2.67 m/s
Hence the wave speed is 2.67 m/s.
Given:
The thermal energy added to the system is Q = 90 J
The work done by the system on the surroundings is W = 30 J
To find the change in internal energy.
Explanation:
According to the first law of thermodynamics, the change in internal energy can be calculated by the formula
On substituting the values, the change in internal energy will be
Final Answer: The chage in internal energy is 60 J (option D)