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Radda [10]
3 years ago
10

A 72.9 kg man stands on a spring scale in an elevator. Starting from rest, the elevator ascends, attaining its maximum speed of

1.21 m/s in 0.80 s. It travels with this constant speed for 4.97 s, undergoes a uniform downward acceleration for 1.52 s, and comes to rest. What does the spring scale register (a) before the elevator starts to move?
Physics
1 answer:
andrew-mc [135]3 years ago
8 0

Answer:

(a) 72.9 kg

Explanation:

Before the elevator starts to move, only gravitational force exerts on the man, this force is generated by the man mass and the gravitational acceleration, which in turn register in the scale. So the scale would probably indicate the man mass, which is 72.9 kg.

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Which sets of data show a wave with the shortest wavelength? A. Speed=100 million m/s and frequency = 50 million Hz. B. Speed=15
SashulF [63]
The answer is <span>A. Speed=100 million m/s and frequency = 50 million Hz.</span>

Let's calculate for each choice the wavelength using the equation:
v = f × λ   ⇒ λ = v ÷ f<span>

where:
v - the speed,
f - the frequency,
</span>λ - the wavelength.

A:
v = 100 000 000 m/s
f = 50 000 000 Hz = 50 000 000 1/s (Since f = 1/T, so units are Hz = 1/s)
⇒ λ = 100 000 000 ÷ 50 000 000 = 2 m

B:
v = 150 000 000 m/s
f = 1 500 Hz = 1 500 1/s
⇒ λ = 150 000 000 m/s ÷ 1 500 = 100 000 m

B:
v = 300 000 000 m/s
f = 100 Hz = 100 1/s
⇒ λ = 300 000 000 m/s ÷ 100 = 3 000 000 m

According to these calculations, the shortest wavelength is needed for choice A.
3 0
3 years ago
A technician attaches one lead of a digital voltmeter to the ground terminal of the TP sensor and the other meter lead to the ne
wariber [46]

Answer:

Neither A or B

Explanation:

The 37.3mv is not the signal voltage

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5 0
3 years ago
A skier pushes off the top of a hill with an initial speed of 3.30 m/s. How fast will she be moving after dropping 5.00 meters i
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8 0
3 years ago
An lc circuit oscillates at a frequency of 2000 Hz. What will the frequency be if the inductance is quadrupled?
Irina-Kira [14]
<h2>Answer:</h2>

An LC circuits if formed by an inductor and a capacitor. The charge on the capacitor and the current through the inductor both vary sinusoidally with time. Also, energy is transferred between magnetic energy in the inductor and electrical energy in the  capacitor. But <em>what happens with the frequency if the inductance is quadrupled? </em>that is, if initially the inductance is L and the frecuency f=2000Hz if now L_{New}=4L What will the frequency be? Well, we know that the frequency, inductance and capacitance are related as:

f=\frac{1}{2\pi}\sqrt{\frac{1}{LC}}

and this equals 2000Hz. If now L is quadrupled:

f_{1}=\frac{1}{2\pi}\sqrt{\frac{1}{4LC}}=\frac{1}{2\pi}\sqrt{\frac{1}{4}}\sqrt{\frac{1}{LC}} \\ \\ \therefore f_{1}=(\frac{1}{2})\frac{1}{2\pi}\sqrt{\frac{1}{LC}} \\ \\ \\ Since \ f=\frac{1}{2\pi}\sqrt{\frac{1}{LC}} \ then: \\ \\ f_{1}=\frac{1}{2}f \therefore f_{1}=\frac{2000}{2} \\ \\ \therefore \boxed{f_{1}=1000Hz}

<em>Finally, if L is quadrupled the frequency is half the original frequency and equals 1000Hz</em>

3 0
3 years ago
Define velocity and also write their mathematical expression​
Archy [21]
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