Answer:
F= 5.71 N
Explanation:
width of door= 0.91 m
door closer torque on door= 5.2 Nm
In order to hold the door in open position we need to exert an equal and opposite torque, to the door closer torque, on the door.
so wee need to exert 5.2 Nm torque on the door.
If we want to apply minimum force to exert the required torque we need to apply force perpendicularly on the door knob (end of door) so that to to greater moment arm.
T= r x F
T= r F sin∅
F= T/ (r * sin∅)
F= 5.2/ (0.91 * 1)
F= 5.71 N
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The answer is D
Hope this helps
serving speed = 170 km/h
now we will convert it into m/s
now it will have two components along x and y directions
also in x and y directions we know
by solving above equation we have
so angle is 6.11 degree below the horizontal
now we have
now time taken by ball to reach the ground will be
now the displacement in x direction will be
now the distance from net will be
So it will land inside the line
<h2>
<u>Given</u>:</h2>
Horizontal distance between two boats = x = 14 m
One boat is at trough, the other is at crest.
As there is no crests between them meaning the boat are next to each other.
Wavelength is the distance between two consecutive crests/troughs = w
The distance between a crest and a trough next to it = w/2
Complete cycles = c = 5
Time taken for c cycles = t = 15 s
Vertical distance between two boats = y = 2.4 m
<h2>
<u>To find</u>:</h2>
wavelength = w = 2x = 28 m
Amplitude = A = Displacement from mean to extreme position = y/2 = 1.2 m
Time period for one cycle = T = t/c = 15/5 = 3 s/cycle
frequency = 1/T = 1/3 = 0.33 hertz
speed = wavelength/Period = w/T = 28/3 = 9.33 m/s