In which situation is work not being done?
1 answer:
AS
work done =W = F.d = F d cosФ (Ф is angle between force F and displacement d) If a body/object is moving on a smooth surface (friction-less surface ) .There is no force acting on that body. F=0 so W=FdcosФ= (0)dcosФ ⇒ W=0
Now if a body is facing some amount of force but under the action of force there is no displacement covered. d=0 so W =FdcosФ= F(0)cosФ ⇒W=0
example: A person is applying a force on rigid wall but wall remains at rest there is no displacement occurs in wall.
The third term upon which work done dependent is angle between force and displacement i.e Ф. If Ф=90° then W= FdcosФ= Fdcos90⇒ W=0 ( as cos 90°=0)
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Answer:
Explanation:
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is the mass of the object and
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Therefore:
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Answer:
speed of water is 0.0007138m/s
Explanation:
From the law of conservation of mass
Rate of mass accumulation inside vessel = mass flow in - mass flow out
so, dm/dt = mass flow in - mass flow out
taking p as density
where,
q(in) is the volume flow rate coming in
Q = is the volume of liquid inside tank at any time
But,
dQ = Adh
where ,
A = area of liquid surface at time t
h = height from bottom at time t
A = πr²
r is the radius of liquid surface
Hence,
so, the speed of water surface at height h
where,
is 75.7 L/min = 0.0757m³/min
h = 1.5m
so,
v = 0.04283 /60
v = 0.0007138m/s
Hence, speed of water is 0.0007138m/s