Answer:
Explanation:
See the attached figure . See the forces acting on man pulling up the box .
Man is stationary so net force acting on man is zero .
T + R = Wman
R is the reaction force of the ground of second floor .
R = Wman - T
Answer:
<em>The power generated is = 5.33×10⁸ Watt. </em>
Explanation:
Power: Power can be defined as the time rate of doing work. The S.I unit of power is <em>Watt(W).</em>
<em>Mathematically,</em>
<em>Power (P) = Work done/time or Energy/time</em>
P = mgh/t............................... Equation 1
P = δgh............................. Equation 2
Where δ = fall rate, g = acceleration due to gravity, h = height.
<em>Given: </em>δ = 1.1×10⁶ kg/s, h = 49.4 m g = 9.81 m/s²
Substituting these values into equation 2
P = 1.1×10⁶×49.4×9.81
P = 533.08×10⁶
<em>P = 5.33×10⁸ Watt.</em>
<em>Thus the power generated is = 5.33×10⁸ Watt. </em>
<span>Answer:
Using 1/f = 1/d' + 1/d ...(where d' object distance and d is image distance)
1/4 = 1/7 + 1/d
1/4 - 1/7 = 1/d
3/28 = 1/d
d = 28/3
d = 9.33 cm</span>
The correct answer is:
<span>C) The actual frequency of the siren does not change despite appearances.
In fact, Bob will observe an increase in the apparent frequency as the emergency vehicle approaches him, while Jill will observe a decrease in the apparent frequency as the emergency vehicle moves away from him, because of the Doppler effect (the relative velocity between the observer and the source of the sound is changing), but this effect involves the apparent frequency, while the real frequency of the siren will remain the same.</span>
