Answer:
1. increases
2. increases
3. increases
Explanation:
Part 1:
First of all, since the box remains at rest, the horizontal net force acting on the box must equal zero:
F1 - fs = 0.
And this friction force fs is:
fs = Nμs,
where μs is the static coefficient of friction, and N is the normal force.
Originally, the normal force N is equal to mg, where m is the mass of the box, and g is the constant of gravity. Now, there is an additional force F2 acting downward on the box, which means it increases the normal force, since the normal force by Newton's third law, is the force due to the surface acting on the box upward:
N = mg + F2.
So, F2 is increasing, that means fs is increasing too.
Part 2:
As explained in the part 1, N = mg + F2. F2 is increasing, so the normal force is thus increasing.
Part 3:
In part 1 and part 2, we know that fs = Nμs, and since the normal force N is increasing, the maximum possible static friction force fs, max is also increasing.
<u>Answer
</u>
A. 1 and 2
<u>Explanation
</u>
At point 1 we have the highest potential energy and the kinetic energy is zero.
At 2 the potential energy is minimum and the kinetic energy is maximum.
The law of conservation of energy says that energy cannot be created nor destroyed. So, the change in P.E = Change in K.E.
P.E = height × gravity × mass. The height referred here is the perpendicular height. Gravity and mass are constant in this case.
From the diagram it can be seen clearly that the vertical height from 2 to 1 is much greater than from 4 to 3.
This shows that the change in P.E is greater between 1 and 2 and so is kinetic energy.
In both cases less energy is required
But comparetively Mg require more energy than K
Let's see the electron configuration of Both
- [Mg]=1s²2s²2p⁶3s²=[Ne]3s²
- [K]=1s²2s²2p⁶3s²3p⁶4s¹=[Ar]4s¹
K has only one valence electron so very less ionization enthalpy so less energy required
Mg has 2 so more IE hence more energy required
That would be a nebula, which is an interstellar cloud of hydrogen gas, dust, and plasma. It is the first stage of a star's cycle.
