Answer:
C. A change has occurred in the nucleus.
Explanation:
The distance covered by car is equal to (assuming it is moving by uniform motion) the product between the car's speed and the time of the car ride, 4 h:

where

is the car's speed

is the duration of the car ride
Similarly, the distance covered by train is equal to the product between the train's speed and the duration of the train ride, 7 h:

The total distance covered is S=255 km, which is the sum of the distances covered by car and train:

which becomes

(1)
we also know that the train speed is 5 km/h greater than the car's speed:

(2)
If we put (2) into (1), we find

and if we solve it, we find


So, the car speed is 20 km/h and the train speed is 25 km/h.
Answer:
Work done in both the cases will be same
Explanation:
As we know that the work done against gravity is given as

here we know that gravitational force is a conservative force and the work done against gravitational force is independent of the path
So here the work done by person to move the object between two different heights will be independent of the path they choose
So for the first person and second person will be same in both the cases because the height through which the boxes are transferred will be same in both the cases
<h2>
Answer:
</h2>
The velocity of a satellite describing a circular orbit is <u>constant</u> and defined by the following expression:
(1)
Where:
is the gravity constant
the mass of the massive body around which the satellite is orbiting
the radius of the orbit (measured from the center of the planet to the satellite).
Note this orbital speed, as well as orbital period, does not depend on the mass of the satellite. I<u>t depends on the mass of the massive body.</u>
In addition, this orbital speed is constant because at all times <u>both the kinetic energy and the potential remain constant</u> in a circular (closed) orbit.
Answer:
Moro reflex
Explanation:
The baby has a series of reflexes in its first months of life and they are very important for the good development of the little ones. One of them is the Moro Reflex. In this reflection, the baby spreads his arms wide, stretches his legs and extends his neck. Moro's reflex begins from birth and continues until about four months of the baby. It occurs when the baby abruptly shifts position or falls backwards or feels in an insecure position, at which time the baby makes a hug movement by arching his back, extending his legs, throwing his arms out and then bringing his arms. towards the body.