Answer:
No machine is free from the effects of gravity, and even with wonderful lubrication, friction always exists. The energy a machine produces is always less than the energy put into it (energy input). ... That is why 100% efficiency in machines shall not be possible.
Answer:
B.
Venus is the same size and density.
Explanation:
It is becuase venus has the same size and density as earth
Answer:
1.The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet that needs no power, an electromagnet requires a continuous supply of current to maintain the magnetic field.
If I did my math right I believe 13 is the 9.3 seconds and 14 is the first option because of logic. The question basically says, how does the height change and the answer is the first one because it gets higher then lower, or increases then decreases.
Explanation:
It is given that,
Work done, W = 240 J
Heat removed, Q = 610 J
(a) The refrigerator's coefficient of performance is given by :


COF = 2.54
(b) Let Q' is the heat per cycle is exhausted to the kitchen. It is given by :
Q' = Q + W
Q' = 610 + 240
Q' = 850 J
Hence, this is the required solution.