Answer: 1479watts
Explanation:
Power is defined as the energy expended or work done in a specific time.
Mathematically,
Power = Workdone/time taken
Since work done is force × distance
Power = force × distance/time
Force = Mary's weight = 87N
Distance = height of the flight = 102meters
Time = 6.0seconds
Substituting in the formula we have;
Power = 87 × 102/6
Power = 1,479watts
Note that the time must be in seconds before usage. If its given in minutes, you will have to convert to seconds
The third one sliding friction
Explanation:
Answer:
<em>To reverse the direction of an electric current, we simply reverse the voltage either automatically with the help of some switching circuitry or manually by changing the voltage source terminals connection. </em>
Explanation:
For electric current to flow, there must be a potential difference, usually referred to as the voltage. The electric current flow is analogous to the flow of water under the action of a pump, through a series of pipe connections. The voltage is similar to the driving action of the pump, and current flows the same way water flows. The resistance due to drag on the pipe wall is equivalent to electric resistance. For current to flow in the reverse direction, the voltage or rather, the potential difference is changed, causing the current to flow in the opposite direction. This can be done by switching the terminals of the voltage source, or by automatic means. The automatic switching can be done with a transistor based circuitry.
Answer:
(a) 62.69 nJ/m^3
(b) 1015.22 μJ/m^3
Explanation:
Electric field, E = 119 V/m
Magnetic field, B = 5.050 x 10^-5 T
(a) Energy density of electric field = 
= 6.269 x 10^-8 J/m^3 = 62.69 nJ/m^3
(b) energy density of magnetic field = 
= 1.01522 x 10^-3 J/m^3 = 1015.22 μJ/m^3
The answer should be B. A half step
