The best and most correct answers among the choices provided by your question are he second and third choices.
<span>The velocity at any instant the average velocity during some time interval cannot be obtained from the graph alone.</span>
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Answer:

Explanation:
At thermal equilibrium we have heat given by aluminium must be equal to the heat absorbed by the water
so we will have


so we will have

so we have

so we have


Answer:
a. by moving the book without acceleration and keeping the height of the book constant
Explanation:
FOR CONSTANT KINETIC ENERGY:
The kinetic energy of a body depends upon its speed according to its formula:
ΔK.E = (1/2)mΔv²
So, for Δv = 0 m/s
ΔK.E = 0 J
So, for keeping kinetic energy constant, the books must be moved at constant speed without acceleration.
FOR CONSTANT POTENTIAL ENERGY:
The potential energy of a body depends upon its height according to its formula:
ΔP.E = mgΔh
So, for Δh = 0 m/s
ΔP.E = 0 J
So, for keeping potential energy constant, the books must be moved at constant height.
So, the correct option is:
<u>a. by moving the book without acceleration and keeping the height of the book constant</u>
Answer:
C. 2 mph
Explanation:
speed equals total distance covered in total time of of travel
since,
total distance = 4 miles
time taken = 2 hrs
speed = 4m / 2hrs =2mph