Answer:
U² = 142.86 N
U¹ = 357.14 N
Explanation:
Taking summation of the moment about point A, we get the following equilibrium equation: (taking clockwise direction as positive)

where,
W = weight of boy = 500 N
U² = reaction ay B = ?
Therefore,

<u>U² = 142.86 N</u>
Now, taking summation of forces on the plank. Taking upward direction as positive, for equilibrium position:

<u>U¹ = 357.14 N</u>
Answer:
the power that can be generated by the river is 117.6 MW
Explanation:
Given that;
Volume flow rate of river v = 240 m³/s
Height above the lake surface a h = 50 m
Amount of power can be generated from this river water after the dam is filled = ?
Now the collected water in the dam contains potential energy which is used for the power generation,
hence, total mechanical energy is due to potential energy alone.
= m(gh)
first we determine the mass flow rate of the fluid m
m = p×v
where p is density ( 1000 kg/m³
so we substitute
m = 1000kg/m³ × 240 m³/s
m = 240000 kg/s
so we plug in our values into (
= m(gh) kJ/kg )
= 240000 × 9.8 × 50
= 117600000 W
= 117.6 MW
Therefore, the power that can be generated by the river is 117.6 MW
Explanation:
By the statement, Efficiency of a machine is 60% it is meant that 'The work output is 60% of the work input'. If you apply 100J of energy for a machine, it will be able to life load of 60 J only
Answer:
1/3 times.
Explanation:
Let V₀ be the peak voltage .
IR ( rms ) = ( V₀ / √2 R )
R is value of resistance
IC = ( V₀ ωC / √2 )
( 1 / ωC is reactance of capacitance in ac circuit )

= 
When frequency is tripled angular frequency will also be tripled
hence the ratio
becomes 1/3 times.
It would be gravity i do beileve