An amount of nitrogen undergoes a physical change and increases its volume. what can be known about this physical change?

the boiling point of the nitrogen increased.
the mass of nitrogen increased.
the color changed.
the density changed.

Correct answer choice is :

D) The density changed.

Explanation:

Density is the number of mass placed in a particular volume. The density of an object can vary if either the mass or volume of the object is modified. Fluids, such as water, have a specific density. If an object is thicker than water, it will sink; if it is less thick than water, it will float. Maximum material rises in volume when it gets hotter. For instance, if an iron rod is ignited, it will get longer and thicker and its density will reduce. This occurs because the mass of the rod stays the equivalent, but its volume rises.

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards