Answer:
B. Same for a chemical family
When dealing with multiple forces acting on a body, it is advisable to draw a free-body diagram like that shown in the picture. There are four forces acting on the box: weight (W) pointing straight down, normal force perpendicular to the slope denoted as Fn, force used to push the box upwards along the slope and the frictional force acting opposite to the direction of motion of the box denoted as Ff. Frictional force is equal to coefficient of kinetic friction (μk) multiplied with Fn.
∑Fy = Fn - mgcos30° = 0
Fn = (50)(9.81)(cos 16) = 471.5 N
When in motion, the net force is equal to mass times acceleration according to Newton's 2nd Law of Motion:
Fnet = F - μk*Fn - mgsin30° = ma
250 - (0.2)(471.5 N) - (50)(sin 16°) = (50)(a)
a = 2.84 m/s²
Answer:
8 KJ/ s
Explanation:
Heat pumps Transfer thermal energy through absorbing of heat that comes from cold region and then release to warmer area by utilizing external power.
The coefficient of performance known as COP provide the ratio of both heating and cooling that are supplied to required work.
✓QH=The rate at which heat is produced = ?
✓COP= Coefficient of performance of a residential heat pump = 1.6
✓ W(in)= power consumption= 5KW
QH=The rate at which heat is produced=[Coefficient of performance of a residential heat pump] × [power consumption]
= 1.6 × 5KW
=8 KJ/ s
Reflection: a change in direction of a wave at a boundary between two different media.
sentence: i saw my reflection in the mirror.
refraction: the bending of light as it passes from one transparent substance into another.
sentence: when light goes through glass, it’s a refraction.
diffraction: the bending of waves around the corners of an obstacle.
sentence: spaced tracks on a CD act as a diffraction.
absorption: the process or action by which one thing absorbs or is absorbed by another.
sentence: heat waves hitting the beach usually give most of their energy to the sand.
interference: when two waves lay on each other and their energies are either added together or cancelled out.
sentence: interference waves can be observed with all types of waves.
standing wave: two waves moving in opposite directions. they both have the same amplitude or frequency.
sentence: plucking the string of a guitar is an example of standing waves.
resonance: increased amplitude that occurs when the frequency of a force is equal or close to a natural frequency.
sentence:a buzz in your car that only occurs at a certain speed is an example or resonance.
Answer:
We would not be able to make our way around the earth's surface, to read, to sculpt or to create technology because we cannot see!
Explanation:
The minimum angular separation that can be distinguished by an eye gives the angular resolution of the eye.
Given that the Angular resolution with infrared radiation is = equal to
This resolution is very much greater than that of the eye
The angular resolution that our eyes can see is about at arms length
Angular resolution of infrared = at arms length
We therefore cannot read, sculpt or create technology because we cannot see.