Answer: Lightning is mostly light and electricity, this light that is hitting is going at a rate of 299,792.458 km per second (or 186,282 miles per second) this is so much compared to sound which only travels at about 761 mph (or approximately 332 meters per second). Fun fact: The lightening you are seeing is that coming back to the cloud because the process happens so fast.
Explanation:
Force is transferred from the moving ball to the stationary ball.
If the tension in the rope is 160 n, - 43200 J work doen by the rope on the skier during a forward displacement of 270 m.
Given,
Tension force in the rope is (T) = 160 N
Displacement of the skier (S) = 270 m
The displacement takes place in forward direction while the direction of the tension in the rope is opposite to it.
Therefore, work done by the rope on the skier is,
![W=T.S](https://tex.z-dn.net/?f=W%3DT.S)
⇒![W=270*160*cos\pi \\W=-43200 J](https://tex.z-dn.net/?f=W%3D270%2A160%2Acos%5Cpi%20%5C%5CW%3D-43200%20J)
Hence work done by the rope is - 43200 J.
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Answer:
![v_x = 1.26 m/s](https://tex.z-dn.net/?f=v_x%20%3D%201.26%20m%2Fs)
Explanation:
given,
weight of swimmer = 510 N
length of ledge, L = 1.75 m
vertical height of the cliff, h = 9 m
speed of the swimmer = ?
horizontal velocity of the swimmer should be that much it can cross the wedge.
distance = speed x time
d = v_x × t
1.75 = v_x × t ........(1)
now,time taken by the swimmer to cover 9 m
initial vertical velocity of the swimmer is zero.
using equation of motion for time calculation
![s = ut +\dfrac{1}{2}gt^2](https://tex.z-dn.net/?f=s%20%3D%20ut%20%2B%5Cdfrac%7B1%7D%7B2%7Dgt%5E2)
![9= 0+\dfrac{1}{2}\times 9.8\times t^2](https://tex.z-dn.net/?f=9%3D%200%2B%5Cdfrac%7B1%7D%7B2%7D%5Ctimes%209.8%5Ctimes%20t%5E2)
t² = 1.938
t = 1.39 s
same time will be taken to cover horizontal distance.
now, from equation 1
1.75 = v_x × 1.39
![v_x = 1.26 m/s](https://tex.z-dn.net/?f=v_x%20%3D%201.26%20m%2Fs)
horizontal speed of the swimmer is equal to 1.26 m/s