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3 years ago

An observer sitting at a bus stop sees the bus drive by at 30 m/s to the east. He also sees a

Physics

1 answer:

Dafna1 [17]3 years ago

8 0

Answer:

32 m/s

Explanation:

The speed of a bus is 30 m/s due East wrt the passenger

He also sees a passenger on the bus walking to the back at 2 m/s.

We need to find the passenger's velocity relative to the bus. As the observer sees that the bus and the passenger are moving in opposite direction. Let v is the relative velocity. So,

v = 30 m/s + 2 m/s

v = 32 m/s

Hence, the passenger's velocity relative to the bus is 32 m/s.

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The Law of Reflection states that the Angle of Incidence will always be

VladimirAG [237]

Answer: option c) equal to the angle of reflection.

HOPE IT HELPS YOU

HAVE A GOOD DAY ❤️☺️

7 0

3 years ago

Find the intensity of a 55 dB sound given I 0=10^-12W/m^2

MakcuM [25]

Answer:

3.16 × $10^{-7}$ W/ $m^{2}$

Explanation:

β(dB)=10 × $log_{10}(\frac{I}{I_{0} })$

$I_{0}$ = $10^{-12}$ W/ $m^{2}$

β=55 dB

Therefore plugging into the equation the values,

55=10 $log_{10}(\frac{I}{ [tex]10^{-12}$ })[/tex]

5.5= $log_{10}(\frac{I}{ [tex]10^{-12}$ })[/tex]

$10^{5.5}$ = $\frac{I}{10^{-12} }$

316227.76× $10^{-12}$ = I

I= 3.16 × $10^{-7}$ W/ $m^{2}$

5 0

3 years ago

The tow spring on a car has a spring constant of 3,086 N / m and is initially stretched 18.00 cm by a 100.0 kg college student o

sdas [7]

Answer:

The velocity of the skateboard is 0.774 m/s.

Explanation:

Given that,

The spring constant of the spring, k = 3086 N/m

The spring is stretched 18 cm or 0.18 m

Mass of the student, m = 100 kg

Potential energy of the spring, $P_f=20\ J$

To find,

The velocity of the car.

Solution,

It is a case of conservation of energy. The total energy of the system remains conserved. So,

$P_i=K_f+P_f$

$\dfrac{1}{2}kx^2=\dfrac{1}{2}mv^2+20$

$\dfrac{1}{2}\times 3086\times (0.18)^2=\dfrac{1}{2}mv^2+20$

$50-20=\dfrac{1}{2}mv^2$

$30=\dfrac{1}{2}mv^2$

$v=\sqrt{\dfrac{60}{100}}$

v = 0.774 m/s

So, the velocity of the skateboard is 0.774 m/s.

7 0

3 years ago

When the displacement of a mass on a spring is 12 a the half of the amplitude, what fraction of the mechanical energy is kinetic

Sveta_85 [38]

You know that when the displacement is equal to the amplitude (A), the velocity is zero, which implies that the kinetic energy (KE) is zeero, so the total mechanical energy (ME) is the potential energy (PE).

And you know that the potential energy, PE, is [ 1/2 ] k (x^2)

Then, use x = A, to calculate the PE in the point where ME = PE.

ME = PE = [1/2] k (A)^2.

At half of the amplitude, x = A/2 => PE = [ 1/2] k (A/2)^2

=> PE = [1/4] { [1/2]k(A)^2 } = .[1/4] ME

So, if PE is 1/4 of ME, KE is 3/4 of ME.

And the answer is 3/4

7 0

3 years ago

The sun can continue to exist in its present stable state for about another

Wewaii [24]

Answer:

5.5 billion years

Explanation:

The answer

3 0

3 years ago

Read 2 more answers