A heat pump is a device that is capable of transferring heat energy from a source of heat to what is known as the heat sink. It also moves thermal energy in the opposite direction of a spontaneous heat transfer through heat absorption from a cold space and releasing it to a warmer space.
When a heat pump is being utilized for heating, it employs the same principle with that of the refrigeration cycle used by an air conditioner or a refrigerator, but in the opposite direction since it releases heat into a conditioned space rather than the surrounding environment. Moreover, heat pump resembles much as refrigeration since it has the same components with the latter except for the presence of a reverse valve.
Answer:

Explanation:
Given that
Radius of track = R
Radius of ball = r
The ball can be treated as solid sphere, so
The moment of inertia of ball

When the ball reach at the lowest position then it will have both angular and linear speed.
Condition for rolling without slipping v= ωr
Form energy conservation

v= ωr






Mechanical weathering is the physical breakdown of rock by environmental factors. This process is always at work, and there are a number of different types of mechanical weathering. Thermal expansion is the tendency for minerals to expand and contract based on temperature.
Answer:
The frequency of the green light is 
Explanation:
The visible region is part of the electromagnetic spectrum, any radiation of that electromagnetic spectrum has a speed of
in the vacuum.
Green light is part of the visible region. Therefore, the frequency can be determined by the following equation:
(1)
Where c is the speed of light,
is the wavelength and
is the frequency.
Notice that since it is electromagnetic radiation, equation 1 can be used. Remember that light propagates in the form of an electromagnetic wave (that is a magnetic field perpendicular to an electric field).
Then,
can be isolated from equation 1
(2)
Notice that it is necessary to express the wavelength in units of meters.
⇒ 
Hence, the frequency of the green light is 
Answer B is the correct answer
We know that kinetic energy
, where m is the mass of object and v is the velocity of object.
In this case only velocity is the variable, mass remains constant.
So point having higher velocity has higher kinetic energy.
When it leaves the racket, the ball will be having a certain height, but just before it reaches the ground it will not having any height. So maximum velocity of ball is at that time when it reaches just above the ground.
So option B is the correct answer.