I think it was Isaac Newton
Answer:
D. Both occur between objects independently whether they are in contact or not.
Explanation:
- The gravitational force is a force that is exerted between two (or more) objects having mass. This force is always attractive and its magnitude is given by

where G is the gravitational constant, m1 and m2 are the two masses, and r is the distance between the two masses.
- The electrical force is a force that is exerted between two (or more) objects having electrical charge. It can be either attractive or repulsive, depending on the sign of the two charges, and its magnitude is given by

where k is the Coulomb's constant, q1 and q2 are the two charges, and r the distance between the two charges.
Looking at both formulas, we see that the two forces are present even when the two objects are not in contact with each other (in fact, r can assume any value in the formula). They are said to be non-contact forces. Therefore, the correct option is
D. Both occur between objects independently whether they are in contact or not.
Answer:
Young's modulus (Y) = 3.56×10^11 N/m^2
The speed of sound in tungsten = 6166.4 m/s
Explanation:
Young's modulus (Y) = stress/strain
Stress = force/area
Force = mg = 30×9.8 = 294 N
Area = 1.5 × 2.6 = 3.9 mm^2 = 3.9/10^6 = 3.9×10^-6 m^2
Stress = 294/3.9×10^-6 = 7.54×10^7 N/m^2
Strain = extension/length
Extension = 0.000594 m
Length = 2.8 m
Strain = 0.000594/2.8 = 2.12×10^-4
Y = 7.54×10^7/2.12×10^-4 = 3.56×10^11 N/m^2
Y = h × rho × g
rho = 18.7 g/cm^3 = 18.7 g/cm^3 × 1 kg/1000 g × (100 cm/1 m)^3 = 18,700 kg/m^3
h = 3.56×10^11/(18,700×9.8) = 1.94×10^6 m
From the equations of motion
v^2 = u^2 + 2gh =
Initial speed (u) = 0 m/s
v = sqrt (2×9.8×1.94×10^6)
v = 6166.4 m/s
Mendeleev created a periodic table with 63 initial elements.
He left gaps for unknown elements.
To this date, there are 118 elements in the periodic table.
The object will move if the forces are unbalanced.
Newtons second tells you that when a net force (the unbalanced force) is applied to and object it will produce an acceleration (movement) in direct proportion to the force and in inverse proportion to the mass of the object.