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2 years ago

PHYSICS!

Physics

1 answer:

Allushta [10]2 years ago

6 0

Answer:

Friction is useful in some cases like walking and cycling ..

but it is unwanted in machines as it create unwanted sounds and heat .,due to which we loss energy

Explanation:

mark me as brainliest ❤️

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Car A (mass 1100 kg) is stopped at a traffic light when it is rearended by car B(mass 1400 kg). Both cars then slide with locke

viva [34]

Answer:

Part a)

$v_a = 3.94 m/s$

Part b)

$v_b = 3.35 m/s$

Part C)

$v_b = 6.44 m/s$

Part d)

Due to large magnitude of friction between road and the car the momentum conservation may not be valid here as momentum conservation is valid only when external force on the system is zero.

Explanation:

Part a)

As we know that car A moves by distance 6.1 m after collision under the frictional force

so the deceleration due to friction is given as

$a = -\frac{F_f}{m}$

$a = -\frac{\mu mg}{m}$

$a = - \mu g$

now we will have

$v_f^2 - v_i^2 = 2ad$

$0 - v_i^2 = 2(-\mu g)(6.1)$

$v_a = \sqrt{(2(0.13)(9.81)(6.1)}$

$v_a = 3.94 m/s$

Part b)

Similarly for car B the distance of stop is given as 4.4 m

so we will have

$v_b = \sqrt{2(0.13)(9.81)(4.4)}$

$v_b = 3.35 m/s$

Part C)

By momentum conservation we will have

$m_1v_{1i} = m_1v_{1f} + m_2v_{2f}$

$1400 v_b = 1100(3.94) + 1400(3.35)$

$v_b = 6.44 m/s$

Part d)

Due to large magnitude of friction between road and the car the momentum conservation may not be valid here as momentum conservation is valid only when external force on the system is zero.

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Three charges are arranged as shown in the picture above. Find the magnitude and direction of the electrostatic force on the 6 n

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Answer:

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Find the wavelength in meters for a transverse mechanical wave with an amplitude of 10 cm and a radian frequency of 20π rad/s if

nydimaria [60]

Answer:

The wavelength of the wave is 20 m.

Explanation:

Given that,

Amplitude = 10 cm

Radial frequency $\omega = 20\pi\ rad/s$

Bulk modulus = 40 MPa

Density = 1000 kg/m³

We need to calculate the velocity of the wave in the medium

Using formula of velocity

$v=\sqrt{\dfrac{k}{\rho}}$

Put the value into the formula

$v=\sqrt{\dfrac{40\times10^{6}}{10^3}}$

$v=200\ m/s$

We need to calculate the wavelength

Using formula of wavelength

$\lambda =\dfrac{v}{f}$

$\lambda=\dfrac{v\times2\pi}{\omega}$

Put the value into the formula

$\lambda=\dfrac{200\times2\pi}{20\pi}$

$\lambda=20\ m$

Hence, The wavelength of the wave is 20 m.

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It is called a pure sound

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