Answer:

Explanation:
An object is at rest along a slope if the net force acting on it is zero. The equation of the forces along the direction parallel to the slope is:
(1)
where
is the component of the weight parallel to the slope, with m being the mass of the object, g the acceleration of gravity,
the angle of the slope
is the frictional force, with
being the coefficient of friction and R the normal reaction of the incline
The equation of the forces along the direction perpendicular to the slope is

where
R is the normal reaction
is the component of the weight perpendicular to the slope
Solving for R,

And substituting into (1)

Re-arranging the equation,

This the condition at which the equilibrium holds: when the tangent of the angle becomes larger than the value of
, the force of friction is no longer able to balance the component of the weight parallel to the slope, and so the object starts sliding down.
Sonar<span> (originally an acronym for Sound Navigation And Ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels.</span>
Answer:
W = 2352 J
Explanation:
Given that:
- mass of the bucket, M = 10 kg
- velocity of pulling the bucket, v = 3

- height of the platform, h = 30 m
- rate of loss of water-mass, m =

Here, according to the given situation the bucket moves at the rate,

The mass varies with the time as,

Consider the time interval between t and t + ∆t. During this time the bucket moves a distance
∆x = 3∆t meters
So, during this interval change in work done,
∆W = m.g∆x
<u>For work calculation:</u>
![W=\int_{0}^{10} [(10-0.4t).g\times 3] dt](https://tex.z-dn.net/?f=W%3D%5Cint_%7B0%7D%5E%7B10%7D%20%5B%2810-0.4t%29.g%5Ctimes%203%5D%20dt)
![W= 3\times 9.8\times [10t-\frac{0.4t^{2}}{2}]^{10}_{0}](https://tex.z-dn.net/?f=W%3D%203%5Ctimes%209.8%5Ctimes%20%5B10t-%5Cfrac%7B0.4t%5E%7B2%7D%7D%7B2%7D%5D%5E%7B10%7D_%7B0%7D)

Answer choice C is a benefit of coal; all the others are negatives.
Feel free to ask me more questions; I'm happy to help. (Don't forget Brainliest!)
Answer:
The answer is A.
Explanation:
The diagram shows the light ray bending away from the normal. Light rays bend away from the normal when their speed increases. This means that in the diagram, the light ray moves from a medium in which light has a lower speed to a medium in light has a higher speed. The only choice where the speed of light increases from A to B is answer A. So that has to be the answer.