Answer: the external agent must do work equal to -1.3 × 10⁻⁸ J
Explanation:
Given that;
Mass M1 = 7.0 kg
r = 3.0/2 m = 1.5 m
Mass M2 = 21 kg
we know that G = 6.67 × 10⁻¹¹ N.m²/kg²
work done by an external agent W = -2GM2M1 / r
so we substitute
W = (-2 × 6.67 × 10⁻¹¹ × 21 × 7) / 1.5
W = -1.96098 × 10⁻⁸ / 1.5
W = -1.3 × 10⁻⁸ J
Therefore the external agent must do work equal to -1.3 × 10⁻⁸ J
Explanation:
Bond Enthalpy : It is defined as amount of energy required to break a the particular bond in there gaseous state. It is also known as bond energy. It units are kJ/mol.
- Breaking of a bond is an Endothermic process (energy absorbed from the surroundings).
- Formation of bond is an Exothermic process (energy is released to the surroundings).
If the average bond enthalpy for a C-H bond is 413 kJ/mol, When the C-H bond breaks in which energy will be required ,which will be an endothermic reaction.
Remark
When you are asked a question like this, the first thing to do is search out a formula and put some limits on it.
Formula
I = E/R which comes from E = IR. To get to the derived formula, divide both sides by R
E/R = I*R/R
E/R = I
Discussion
This is an inverse relationship. That means that as one goes up the other one will go down.
So in this case you keep E constant and you manipulate R and look at your results for I
Case 1
Let us say that E = 10 volts
Let us also say the R = 10 ohms
I = E/R
I = 10/10
I = 1 ohm
Case Two
Let's raise the Resistance to 100 ohms
E = 10
R = 100
I = 10/100 = 0.1
Conclusion
As the Resistance goes up, the current goes down. Answer: A
