d)The unit for work is a joule. The unit for power is a watt, which is a joule per second.
Answer:
Option (d) is correct.
Explanation:
Work done is given by :
W = Fd, where F is force and d is displacement
Unit of work done :
The SI unit of force is Newton (N) and that of displacement is meter (m). So, the unit of work done is N-m. It is call Joule. It means that the unit of work done is Joule.
Power is given by rate at which the work is done. It is given by :
P = W/t, W is work done and t is time
Unit of power:
Unit of work is Joule (J) and that of time is second (s). It means that the unit of power is Watt and it is equal to Joule/second
Hence, the correct option is (d) "The unit for work is a joule. The unit for power is a watt, which is a joule per second".
Answer: The unit for work is a joule. The unit for power is a watt, which is a joule per second.
Explanation:
The speed a spherical raindrop would achieve falling from 3950 m in the absence of air drag is calculated by firstly finding the time it takes for the raindrop to fall this distance using equations of motion, and then using this time in the equation for final velocity. The calculated speed is approximately 2785.30 m/s.
To calculate the speed a spherical raindrop would achieve falling from 3950 m in the absence of air drag, we must recall the equations of motion. The relevant equation here is Final velocity (v) = Initial velocity (u) + Acceleration (gravity, g) * time (t). However, since initial velocity (u) is 0 (when the drop starts falling, it's stationary), the equation simplifies to Final velocity (v) = g * t.
In free fall, a body accelerates under gravity (approximated as 9.81 m/s^2). In terms of time, difficulties arise because we don't know exactly when the raindrop will hit the ground. We can, however, calculate the time it would take for the raindrop to fall 3950 m by rearranging the equation distance (s) = ut + 0.5 * g * t^2 to solve for time. Removing (u), for the reasons explained earlier, we have the equation s = 0.5 * g * t^2. Solving this for time gives t = sqrt(s / (0.5 * g)). Substituting the given fall distance for s we get t = sqrt(3950 / (0.5 * 9.81)) or approximately 284.10 seconds.
Finally, we use this calculated time in our simplified velocity equation which gives v = g * t or 9.81 * 284.10, which equals approximately 2785.30 m/s.
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