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k0ka [10]
3 years ago
12

A train moving at a constant speed is passing a stationary observer on a platform. On one of the train cars, a flute player is c

ontinually playing the note known as concert A (f = 440 Hz). After the flute has passed, the observer hears the sound with a frequency of 415 Hz. What is the speed of the train? The speed of sound in air is 343 m/s.
Physics
1 answer:
Ilya [14]3 years ago
8 0

Answer:

Explanation:

We shall apply the formula of Doppler effect here

F( APPARENT) = F( REAL ) X V/(V + Vs) [ v is velocity of sound and Vs is velocity of source.

415 = 440 X 343/343+Vs

142345 + 415Vs = 150920

415 V₀ = 8575

V₀ = 20.66 m/s.

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Formula One racers speed up much more quickly than normal passenger vehicles, and they also can stop in a much shorter distance.
klasskru [66]

Answer:

The magnitude of the car's acceleration as it slows during braking is 36.81 m/s²

Explanation:

From the question, the given values are as follows:

Initial velocity, u = 90 m/s

final velocity, v = 0 m/s

distance, s = 110 m

acceleration, a = ?

Using the equation of motion, v² = u² + 2as

(90)² + 2 * 110 * a = 0

8100 + 220a = 0

220a = -8100

a = -8100/220

a = -36.81 m/s²

The value for acceleration is negative showing that car is decelerating to a stop. The magnitude of the car's acceleration as it slows during braking is therefore 36.81 m/s²

4 0
3 years ago
Which object has the most Kinetic Energy, and why?
Ilya [14]
A small rock quickly rolling down a hill because as the velocity or speed increases the particles in the rock start to increase kinetic energy. The particles start to act up and create more energy. Also because the small rock would go faster than a giant rock because of Newton's second law. Can I have brainliest pls?
6 0
2 years ago
Read 2 more answers
What is a safe following distance between your automobile and the vehicle in front of you?
Colt1911 [192]

Answer:

Many drivers follow the “three-second rule.” In other words, you should keep three seconds worth of space between your car and the car in front of you in order to maintain a safe following distance.

Thank you and please rate me as brainliest as it will help me to level up

4 0
2 years ago
A horizontal spring with spring constant 130 N/m is compressed 17 cm and used to launch a 2.8 kg box across a frictionless, hori
olasank [31]

Explanation:

The given data is as follows.

        k = 130 N/m,       \Delta x = 17 cm = 0.17 m   (as 1 m = 100 cm)

     mass (m) = 2.8 kg

When the spring is compressed then energy stored in it is as follows.

             Energy = \frac{1}{2}kx^{2}

Now, spring energy gets converted into kinetic energy when the box is launched.

So,    \frac{1}{2}kx^{2} = \frac{1}{2}mv^{2}

   \frac{1}{2} \times 130 \times (0.17)^{2} = \frac{1}{2} \times 2.8 \times v^{2}

          v^{2} = \frac{3.757}{2.8}

                     = 1.34

                v = 1.15 m/sec

Now,

           Frictional force = \mu \times mg

                                    = 0.15 \times 2.8 \times 9.8

                                    = 4.116 N

Also,  Kinetic energy = work done by friction

           \frac{1}{2}mv^{2} = F_{f} \times d

           \frac{1}{2} \times 2.8 \times (1.15)^{2} = 4.116 \times d

             1.8515 = 4.116 \times d

                 d = 0.449 m

Thus, we can conclude that the box slides 0.449 m across the rough surface before stopping.

8 0
3 years ago
What are non-contact forces please include example in your answer
Alina [70]

Answer:

Gravitational force.  Magnetic force.  Electrostatics.  Nuclear force.

Explanation:

Apple falling from a tree

raindrops falling from the sky

4 0
3 years ago
Read 2 more answers
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