Answer:
Explanation:
The answer you should pick is A. Two magnets will attract each other when their poles are opposite and they are close together.
Option a; Electric field can accelerate an electron, but never change its speed
An electric field (also known as an E-field) is a physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It can also refer to the physical field of a charged particle system. Electric fields are created by electric charges and time-varying electric currents. Electric and magnetic fields are both aspects of the electromagnetic field, one of nature's four fundamental interactions (also known as forces). Electric fields are significant in many areas of physics and are used in electrical technology. In atomic physics and chemistry, for example, the electric field is the attractive force that holds the atomic nucleus and electrons together in atoms. It is also the driving force behind chemical bonds between atoms.
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Answer:
change in entropy is 1.44 kJ/ K
Explanation:
from steam tables
At 150 kPa
specific volume
Vf = 0.001053 m^3/kg
vg = 1.1594 m^3/kg
specific entropy values are
Sf = 1.4337 kJ/kg K
Sfg = 5.789 kJ/kg
initial specific volume is calculated as
FROM STEAM Table
at 200 kPa
specific volume
Vf = 0.001061 m^3/kg
vg = 0.88578 m^3/kg
specific entropy values are
Sf = 1.5302 kJ/kg K
Sfg = 5.5698 kJ/kg
constant volume so
Change in entropy 
=3( 3.36035 - 2.88) = 1.44 kJ/kg
<span>2.5 m/s going upward.
In the situation described, Erica and Danny undergo a non-elastic collision which will conserve their combined momentum. Since Erica is stationary, her momentum is 0. And since Danny is moving upward at 4.7 m/s his momentum is 43 kg * 4.7 m/s = 202.1 kg*m/s. Assuming that both Erica and Danny will be moving as a joined system, their combined mass is 38 kg + 43 kg = 81 kg. Since the momentum will be the same, their velocity will be 202.1 kg*m/s / 81 kg = 2.495061728 m/s. Since we only have 2 significant figures in the provided data, rounding the result to 2 significant figures gives a velocity of 2.5 m/s going upward.</span>
