Answer:
a 
b
Explanation:
Generally the force constant is mathematically represented as

substituting values given in the question
=> 
=> 
Generally the workdone in stretching the spring 3.5 m is mathematically represented as

=> 
=> 
Generally the workdone in compressing the spring 2.5 m is mathematically represented as
=>
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Answer: A
Explanation:
From the figure given as attachments, the error pointing upward signifies the incident ray while the one point downwards signifies the reflected ray.
One of the laws of reflection is stated that the angle of incidence is equal to the angle of reflection.
Since the two arrows are parallel to each other, then the mirror must be perpendicular to the two arrows. That is, the incident ray and the reflected ray must be perpendicular to the mirror.
Option A is the correct answer.
The answer is that it is 1.5 amps
A) diagram is shown on the image below
b) Mass m = 450/9.8 = 45.918 KgNet upward force = T + T = 2T = 620 NNet downward force = 290 + 160 = 450 NResultant force F = Net upward force - Net downward force ma = 620 - 450 45.918 a = 170 Acceleration a = 170/45.918 =
3.7 m/s^2 (upward)Here Net upward force > Net downward force, So the resultant force directed upwards, hence acceleration will be
upward.
(c)Consider the case of boy alone, then from Newtons law of motion we can write Net force F = n + T - 290 ma = n + 310 - 290 where m = 290/9.8 = 29.59 Kg 29.59 * 3.7 = n + 20 109.483 = n + 20 n =
89.483 N