A construction worker runs a jack hammer for 1.5 hours. The jack hammer has 2.4 kilowatts of power. How much electrical energy d
1 answer:
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Answer:
option E
Explanation:
given,
diameter = 4 mm
shutter speed = 1/1000 s
diameter of aperture = ?
shutter speed = 1/250 s
exposure time to the shutter time
N is the diameter of the aperture and t is the time of exposure
now,
inserting all the values
N₂² = 4
N₂ = 2 mm
hence , the correct answer is option E
Answer:
Explanation:
Newton's 2nd Law relates the net force <em>F</em> on an object of mass <em>m </em>with the acceleration <em>a</em> it experiments by <em>F=ma.</em> In our case the net force is the friction force, since it's the only one the skier is experimenting horizontally and the vertical ones cancel out since he's not moving in that direction. Our acceleration then will be:
Also, acceleration is defined by the change of velocity in a given time t, so we have:
Since we want the change in velocity, <em>mixing both equations</em> we conclude that:
Which for our values means: