<span>An imaginary line perpendicular to a reflecting surface is called "a normal" (principle line)
So, Your Answer would be Option B
Hope this helps!</span>

<u>Given :</u>








<u>Let's Slove :</u><u> </u>



The work done by the applied force on the block against the frictional force is 15.75 J.
<h3>
Work done by the applied force</h3>
The work done by the applied force is calculated as follows;
W = Fd
F - Ff = ma
where;
- F is applied force
- Ff is frictional force
Fcos(37) - μmgsin(37) = ma
Fcos(37) - (0.3)(4)(9.8)sin(37) = 4(0.2)
0.799F - 7.077 = 0.8
F = 9.86 N
W = Fdcosθ
W = 9.86 x 2 x cos(37)
W = 15.75 J
Thus, the work done by the applied force on the block against the frictional force is 15.75 J.
Learn more about work done here: brainly.com/question/25573309
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Answer:
a. 250kg I think it's the right answer. hope it helps:)
Answer:
Explanation:
Given
mass of lead piece 
mass of water in calorimeter 
Initial temperature of water 
Initial temperature of lead piece 
we know heat capacity of lead and water are
and
respectively
Let us take
be the final temperature of the system
Conserving energy
heat lost by lead=heat gained by water




