As we know that block of steel is continue to be in moving state
so here the friction must be kinetic friction between two surface
so we know that formula of kinetic friction must be
now we have
now from the above equation we have
So here we need atleast 14.25 N force to continue sliding the box now as per given options all forces which are less than 14.25 N is not correct
Hence correct answer must be 18.0 N
<u>D) 18.0 N</u>
Answer:
Explanation:
Knowing that the volume of a sphere is V=(4/3)πr³ and 
We must find 
when r=14cm
V=(4/3)πr³ ⇒
and r=14cm then
Note: as you can see the relationship of change of r with respect to t is negative because it is a decrease, and also its volume ratio
See below.
The following are the guidelines for creating ray diagrams for the generation of an image by a concave mirror:
Rule 1: If the incident ray is parallel to the major axis, the reflected ray will pass through the concave mirror's focus.
The reflected ray is parallel to the principal axis if the incident ray passes through the focus of the concave mirror.
Rule 3: If the incident ray passes through the concave mirror's center of curvature, the reflected ray follows the same path.
Hope this helps!
Answer:
Earth's magnetic field deviates high energy particles (e.g cosmic rays) that are a risk for human health.
Explanation:
Cosmic rays are high energy charged particles (88% protons, 10% nuclei of helium, 1% heavier nuclei) that came from the outer space. The energies of these particles are in the range of 1 GeV to 10⁸ TeV. Since they are charged particles, they will be deviated by Earth’s magnetic field¹ (as a reminder: A magnetic field applies a magnetic force over a moving charged particle).
Earth’s magnetic field works as a shield to humans against high energy charged particles, if cosmic rays were in touch with a human body, it can break molecules that forms DNA structure². Modifying that structure can lead to diseases as cancer, for example.
Units:
GeV: Giga-electronvolt
TeV: Tera-electronvolt
¹Magnetic field: It is generated around the space of a moving charged particle.
²DNA structure: It is a compound of different molecules that provides information to cells functionality.
2.5 joules according to the formula k=1/2MVsquare we would get 2.5 joules as the answer
