Explanation:
Let us calculate the work done in lifting an object of mass m through a height h, such as in Figure 1. If the object is lifted straight up at constant speed, then the force needed to lift it is equal to its weight mg. The work done on the mass is then W = Fd = mgh. We define this to be the gravitational potential energy (PEg) put into (or gained by) the object-Earth system. This energy is associated with the state of separation between two objects that attract each other by the gravitational force
Potential energy is a property of a system rather than of a single object—due to its physical position. An object’s gravitational potential is due to its position relative to the surroundings within the Earth-object system. The force applied to the object is an external force, from outside the system. When it does positive work it increases the gravitational potential energy of the system. Because gravitational potential energy depends on relative position, we need a reference level at which to set the potential energy equal to 0. We usually choose this point to be Earth’s surface, but this point is arbitrary; what is important is the difference in gravitational potential energy, because this difference is what relates to the work done. The difference in gravitational potential energy of an object (in the Earth-object system) between two rungs of a ladder will be the same for the first two rungs as for the last two rungs.
Answer:
5.15J
Explanation:
First. 54% of the 7kg refrigerant is liquid
So we find mass of vapour at inlet generator
M1 = ( 1-0.54)*7= 3.2kg
At compressor mass of vapour will be
M2= 0.95*7= 6.7kg
So the Mass of vapour at exit generator is
M2-M1= 3.5kg
So to find heat absorbed by refrigerant in evaporation
Its using
Q= mh
°= 3.5x 1.50×10^5 J/kg
=5.15J
Answer:
Part a)
Part b)
Part c)
Explanation:
Part a)
As we know that frequency = 1 MHz
speed of electromagnetic wave is same as speed of light
So the wavelength is given as
Part b)
As we know the relation between electric field and magnetic field
Part c)
Intensity of wave is given as
Pressure is defined as ratio of intensity and speed
