A method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.
Answer:


Explanation:
r = Radius = 2.7 cm
F = Force = 
A = Area = 
= Stress = 
E = Young's modulus = 
= Strain
= Original length = 67 cm
= Change in length
Young's modulus is given by

Strain is 
Strain is given by

The cylinder height decreases by 
It is the the ecrins of light
Answer: 3 m.
Explanation:
Neglecting the mass of the seesaw, in order the seesaw to be balanced, the sum of the torques created by gravity acting on both children must be 0.
As we are asked to locate Jack at some distance from the fulcrum, we can take torques regarding the fulcrum, which is located at just in the middle of the length of the seesaw.
If we choose the counterclockwise direction as positive, we can write the torque equation as follows (assuming that Jill sits at the left end of the seesaw):
mJill* 5m -mJack* d = 0
60 kg*5 m -100 kg* d =0
Solving for d:
d = 3 m.