Answer:
(b) the point charge is moved outside the sphere
Explanation:
Gauss' Law states that the electric flux of a closed surface is equal to the enclosed charge divided by permittivity of the medium.
According to this law, any charge outside the surface has no effect at all. Therefore (a) is not correct.
If the point charge is moved off the center, the points on the surface close to the charge will have higher flux and the points further away from the charge will have lesser flux. But as a result, the total flux will not change, because the enclosed charge is the same.
Therefore, (c) and (d) is not correct, because the enclosed charge is unchanged.
If the force is removed, then there are no other forces acting on the object, the object will continue to move at constant velocity, meaning that it would move in a line tangent to the circular path.
Answer:
F=248.5W N
Explanation:
Newton's 2nd Law tells us that F=ma. We will use their averages always. The average acceleration the tennis ball experimented is, by definition:
Since we start counting at 0s and the ball departs from rest, this is just 
So we can write:
Where in the last step we have just multiplied and divided by g, the acceleration of gravity. This allows us to introduce the weight of the ball W since W=gm, so we have:
Substituting our values:
Where the average force exerted has been written it terms of the tennis ball's weight W.
They would use the Scientific method
"2 km/hr/s" means that in each second, its engines can increase its speed by 2 km/hr.
If it keeps doing that for 30 seconds, its speed has increased by 60 km/hr.
On top of the initial speed of 20 km/hr, that's 80 km/hr at the end of the 30 seconds.
This whole discussion is of <em>speed</em>, not velocity. Surely, in high school physics,
you've learned the difference by now. There's no information in the question that
says anything about the train's <em>direction</em>, and it was wrong to mention velocity in
the question. This whole thing could have been taking place on a curved section
of track. If that were the case, it would have taken a team of ace engineers, cranking
their Curtas, to describe what was happening to the velocity. Better to just stick with
speed.
