Answer:
Circle Q
Explanation:
The flux of a field through a surface is given by:
where
F is the field strength
A is the area of the surface
is the angle between the direction of the field and the normal to the surface
In the figure, we see that the 4 surfaces have different orientations, so different angle . In the formula, we see that the flux is maximum when 
, which occurs when the field is perpendicular to the surface, and the flux is zero when 
, (because 
) which occurs when the field is parallel to the surface.
In the figure, we see that circle Q is parallel to the direction of the field, so in this case the field is zero, while in all the other cases is not.
So, the correct answer is
Circle Q
Answer:
* roller skates and ice skates.
* roller coaster
Explanation:
One of the best examples for this situation is when we are skating, in the initial part we must create work with a force, it compensates to move, after this the external force stops working and we continue movements with kinetic energy, if there are some ramps, we can going up, where the kinetic energy is transformed into potential energy and when going down again it is transformed into kinetic energy. This is true for both roller skates and ice skates.
Another example is the roller coaster, in this case the motor creates work to increase the energy of the car by raising it, when it reaches the top the motor is disconnected, and all the movement is carried out with changes in kinetic and potential energy. In the upper part the energy is almost all potential, it only has the kinetic energy necessary to continue the movement and in the lower part it is all kinetic; At the end of the tour, the brakes are applied that bring about the non-conservative forces that decrease the mechanical energy, transforming it into heat.
Answer:
|F| = 393750 N
Explanation:
Given that,
Total mass of the train, m = 750000 kg
Initial speed, u = 84 m/s
Final speed, v = 42 m/s
Time, t = 80 s
We need to find the net force acting on the train. The formula for force is given by :
F = ma
So, the magnitude of net force is 393750 N.
The correct answer is C:
Many used rational thought and empirical evidence to explain the world around them. Hope this helped!!
