The power of a purely resistive lead is always positive although the current and voltage are sometimes negative. explain
1 answer:
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Answer:
Moment of the force is 20 N-m.
Explanation:
Given:
Force exerted by the person is,
Distance of application of force from the point about which moment is needed is,
Now, we know that, moment of a force 'F' about a point at a perpendicular distance of 'd' from the same point is given as the product of the force and the perpendicular distance.
Therefore, the moment of the force about the end of the claw hammer is given as:
Hence, the moment of the force exerted by the person about the end of the claw hammer is 20 N-m.
Answer:
The observed frequency by the pedestrian is 424 Hz.
Explanation:
Given;
frequency of the source, Fs = 400 Hz
speed of the car as it approaches the stationary observer, Vs = 20 m/s
Based on Doppler effect, as the car the approaches the stationary observer, the observed frequency will be higher than the transmitted (source) frequency because of decrease in distance between the car and the observer.
The observed frequency is calculated as;
where;
F₀ is the observed frequency
v is the speed of sound in air = 340 m/s
F₀ ≅ 424 Hz.
Therefore, the observed frequency by the pedestrian is 424 Hz.