<h2>
Answer: Gravity force</h2>
If we approximate the orbit of the planets around the Sun to circular orbits with a uniform circular motion, where the velocity 
is a vector, whose direction is perpendicular to the radius 
of the trajectory; the acceleration 
is directed towards the center of the circumference (that's why it's called centripetal acceleration).
Now, according to Newton's 2nd law, the force 
is directly proportional and in the same direction as the acceleration:
Therefore the net force resulting from the movement of a planet orbiting the Sun points towards the center of the circle, this is called Centripetal Force which is a central force that in this case is equal to the gravity force.
<u>Answer:</u>
The velocity is 30.279 m/s
<u>Explanation</u>:
Consider the initial speed of the semi-trailer be v
Then, initial kinetic energy = 
According to question, the semi-trailer coast along a ramp, which is inclined at an angle of 170, and to a distance of 160m to stop
Change in vertical position =
= 46.779m
Final potential energy of semitrailer = mgh
Applying principle of conservation of energy,
= mgh
Solving for v, we get 
= 2gh = 2*9.8*46.779 = 916.8684
= 916.8684
v = 30.279 m/s
Therefore, the velocity is 30.279 m/s
Answer:
The process by which the balloon is attracted and possibly sticks to the wall is known as static electricity which is the attraction or repulsion between electric charges which are not free to move.
The wall is an insulator.
Explanation:
When a balloon is blown and tied off, and then the balloon is rubbed on the woolly object once in one direction, and the side that was rubbed against the wool is brought near a wall and then released, it is observed that the balloon is attracted to and sticks to the wall. The above observation is due to static electricity.
Static electricity refers to electric charges that are not free to move or that are static. One of the means of generating such charges is by friction. When the balloon is rubbed on the woollen material, electrons are given away to the balloon's surface. Since the balloon is an insulator (materials which do not allow electricity to pass through them easily), the electrons are not free to move. When the balloon is brought near to a wall, there is a rearrangement of the charges present on the wall. Negative charges on the wall move farther away while the positive charges on the wall are attracted to the electrons on the balloon's surface. Because the wall is also an insulator, the charges are not discharged immediately. Therefore, this attraction between opposite charges as well as the static nature of the charges results in the balloon sticking to the wall.
We have all the charges for q1, q2, and q3.
Since k = 8.988x10^2, and N=m^2/c^2
F(1) = F (2on1) + F (3on1)
F(2on1) = k |q1 q2| / r(the distance between the two)^2
k^ | 3x10^-6 x -5 x 10^-6 | / (.2m)^2
F(2on1) = 3.37 N
Since F1 is 7N,
F(1) = F (2on1) + F (3on1)
7N = 3.37 N + F (3on1)
Since it wil be going in the negative direction,
-7N = 3.37 N + F (3on1)
F(3on1) = -10.37N
F(3on1) = k |q1 q3| / r(the distance between the two)^2
r^2 x F(3on1) = k |q1 q3|
r = sqrt of k |q1 q3| / F(3on1)
= .144 m (distance between q1 and q3)
0 - .144m
So it's located in -.144m
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