The distance from the centre of the rule at which a 2N weight must be suspend from A is 29.3 cm.
<h3>Distance from the center of the meter rule</h3>
The distance from the centre of the rule at which a 2N weight must be suspend from A is calculated as follows;
-----------------------------------------------------------------
20 A (30 - x)↓ x ↓ 20 cm B 30 cm
2N 0.9N
Let the center of the meter rule = 50 cm
take moment about the center;
2(30 - x) + 0.9(x)(30 - x) = 0.9(20)
(30 - x)(2 + 0.9x) = 18
60 + 27x - 2x - 0.9x² = 18
60 + 25x - 0.9x² = 18
0.9x² - 25x - 42 = 0
x = 29.3 cm
Thus, the distance from the centre of the rule at which a 2N weight must be suspend from A is 29.3 cm.
Learn more about brainly.com/question/874205 here:
#SPJ1
Answer:
Explanation:
It is given that,
Initially, the electron is in n = 7 energy level. When it relaxes to a lower energy level, emitting light of 397 nm. We need to find the value of n for the level to which the electron relaxed. It can be calculate using the formula as :
R = Rydberg constant, 
Solving above equation we get the value of final n is,
or
So, it will relax in the n = 2. Hence, this is the required solution.
The statement about "<span>Power is the time rate of change of work" is true. The answer is letter A. Power is presented by the equation P = Wt where P is the power, W is work and t is time.</span>
In one of the greatest coincidences to arise on Brainly in quite some time, Choice-C is the correct choice for BOTH #15 and #16 .
Choice-C is the only situation in which the source is a different distance from each ear.
