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In physics, power is the rate of doing work or of transferring heat, i.e. the amount of energy transferred or converted per unit time. Having no direction, it is a scalarquantity. In the International System of Units, the unit of power is the joule per second (J/s), known as the watt in honour of James Watt, the eighteenth-century developer of the condenser steam engine. Another common and traditional measure is horsepower (comparing to the power of a horse). Being the rate of work, the equation for power can be written:
Power
Common symbols
Derivations from
other quantities
P = E/t
P = F·v
P = V·I
P = T·ω
As a physical concept, power requires both a change in the physical system and a specified time in which the change occurs. This is distinct from the concept of work, which is only measured in terms of a net change in the state of the physical system. The same amount of work is done when carrying a load up a flight of stairs whether the person carrying it walks or runs, but more power is needed for running because the work is done in a shorter amount of time.
The original width was 94.71 cm
<span>The area decreased 33.1% </span>
<span>The equation for the final size is </span>
<span>2X^2 = 1.2 m^2 </span>
<span>X^2 - 0.6 m^2 </span>
<span>X^2 = 10000 * .6 cm </span>
<span>X = 77.46 cm (this is the width) </span>
<span>The length is 2 * 77.46 = 154.92 cm </span>
<span>The original length was 154.92 + 34.5 = 189.42 cm </span>
<span>The original width was 189.42 / 2 = 94.71 cm </span>
<span>The original area was 94.71 * 189.92 = 17939.9 cm^2 </span>
<span>The new area is 79.46 * 154.92 = 12000.1 cm^2 </span>
<span>The difference between the original and current area is 17939.9 - 12000.1 = 5939.86 cm^2 </span>
<span>The percentage the area decreased is 5939.86 ' 17939.9 = 33.1%</span>
Because the box keeps going straight at the same speed, while the seat under it speeds up, slows down, or changes direction.
To solve this problem it is necessary to apply the concepts related to the conservation of the Momentum describing the inelastic collision of two bodies. By definition the collision between the two bodies is given as:
Where,
= Mass of each object
= Initial Velocity of Each object
= Final Velocity
Our values are given as
Replacing we have that
Therefore the the velocity of the 3220 kg car before the collision was 0.8224m/s
Answer:
M.A = load/ effort
1200N/400N
= 3
velocity ratio= radius of wheel/radius of Axle
40cm/10cm
=4
efficiency= 3/4*100
75%
