The flow of Direct current (DC) is constant and flows in one direction. Most digital electronics make use of DC. Alternating current (AC) periodically flows in reverse and is mostly used to deliver power to houses, buildings and the like. With that alone, you can already rule out A, C and D.
The answer would then be B. constant, periodically reversing.
The right answer would be
-20t+ 80
Force required to move a block is 1.615 N
Given:
mass of block = m = 150 pounds = 68 kg
distance = d = 5 ft = 1.52 metres
time = t = 8 sec
To Find:
force required to move the block
Solution: Force is defined as product of mass and acceleration and it's unit is N or Newton.
Velocity = displacement/ time = 1.52 / 8 = 0.19 m/s
Acceleration = velocity/time = 0.19/8 =
0.023 m/s^2
Force = mass x acceleration = 68x0.023 = 1.615 N
Hence, force required to move the block is 1.615 N
Learn more about Force here:
brainly.com/question/12970081
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Answer: having to push a rough and heavy box across the floor to move it
Explanation:
The Friction force is any force that is in opposite direction of the motion of an object or fluid due to the contact of this object or fluid with other bodies.
In this sense, there are different types of friction force thath are useful in different situations:
-The <u>Static friction force</u> prevents surfaces from slipping across each other. For example, the friction between your feet and the floor keeping you from slipping.
-The <u>kinetic friction force</u> as the force that helps the tires in a moving vehicle to slow down and stop when necessary.
However, if you want to push a heavy box across the floor to move it, the friction force will not be useful at all.
