Answer:
A an Oxygen isotope
Explanation:
The number of protons is the Same as the atomic number
The atomic number is 9 is the atom has 9 protons
Thus, the atom is an oxygen isotope
Answers is F=7.84 N
Friction force resists the effect of horizontal force and trying to approch to a limiting force.
we have formula for limiting friction force between block and floor
F=Ц N
where N=mg
putting values we get answer.
Answer:Principle of rectilinear propagation of light
Explanation:Principle of rectilinear propagation of light
Rectilinear propagation of light refers to the propensity of light to travel along a straight line without any interference in its trajectory. ... It is because light travels along a straight line and leaves only the areas where the object interferes.
To solve this problem we will apply the concepts related to equilibrium, for this specific case, through the sum of torques.

If the distance in which the 600lb are applied is 6in, we will have to add the unknown Force sum, at a distance of 27in - 6in will be equivalent to that required to move the object. So,



So, Force that must be applied at the long end in order to lift a 600lb object to the short end is 171.42lb