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3 years ago

NEED HELP ASAP

Physics

1 answer:

katrin [286]3 years ago

8 0

Answer:

its In most solids, conduction takes place as particles vibrate in place.

Explanation:

i did it in a test

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A railroad train is traveling at a speed of 26.0 m/s in still air. The frequency of the note emitted by the locomotive whistle i

olga55 [171]

Answer: 0.757m; 0.881m; 432.70Hz; 371.89Hz

Explanation:

Give the following :

Velocity of train (Vt) = 26m/s

Frequency of sound (Fs) = 420Hz

Speed of sound (Vs) = 344m/s

1) wavelength = (Vs - Vt) / Fs

Wavelength = (344 - 26) / 420 = 318/420 = 0.757m

11) Wavelength = (Vs + Vt) / Fs

Wavelength = (344 + 26) / 420 = 370/420 = 0.881m

111) According to the doppler effect :

Fl = [(V + Vl) / (V + Vs)] * fs

Fl = frequency of listener ; fs = frequency of sound source ; V = speed of sound ; Vl = Velocity of listener ; Vs = speed of sound source

Vs = - ve (train moving towards listener)

Fl = [(V + Vl) / (V + Vs)] * fs

Fl = [(344 + 0) / (344 - 26)] * 400

Fl = (344 / 318) * 400 = 432.70Hz

1V) Vs = + ve (train moving away listener)

Fl = [(V + Vl) / (V + Vs)] * fs

Fl = [(344 + 0) / (344 + 26)] * 400

Fl = (344 / 370) * 400 = 371.89Hz

6 0

3 years ago

A cannon fires a 40.5kg shell toward a target and the shell moves with a velocity of 120 m/s. Calculate the shells momentum

kvv77 [185]

Answer:

4860 kg m/s

Explanation:

P = mv

P = 40.5 x 120

P = 4860 kg m/s

8 0

2 years ago

How high must you lift a 25 Newton book for it to have the same increase in potential energy as a 20 Newton book that was lifted

Annette [7]

Given :

An object with weight 20 N was lifted to 0.5 meters.

To Find :

How high must you lift a 25 Newton book for it to have the same increase in potential energy as the given book.

Solution :

Since both have same potential energy :

$P.E_2 = P.E_1\\\\W_2h_2 = W_1h_1$

Putting all given values in above equation :

$25h_2 = 20\times 0.5\\\\h_2 = \dfrac{20\times 0.5}{25}\\\\h_2 = 0.4\ m$

Therefore, book with same potential energy is at a height of 0.4 m.

4 0

3 years ago

The driver of a car applies the brakes for 4.0 s.As a result an average force of 7500N is exerted in the car to slow it down.Wha

Sindrei [870]

Answer:

The change in momentum of the car is 30,000 kg m/s

Explanation:

Given,

The force exerted on the car to slow down, F = 7500 N

The time period of force, t = 4 s

The rate of change of momentum of the object is equal to the force acting on it.

Therefore,

Where v and u are the final and initial velocity of the car. The change in momentum of the car,

mv - mu = F x t

= 7500 x 4

= 30,000 kg m/s

Hence the change in momentum of the car is 30,000 kg m/s

7 0

3 years ago

The useful power output from the motor is 1.5 kW

zaharov [31]

Answer:

t = 300 seconds

Explanation:

Given that,

The power output of the motor, P = 1.5 kW

Energy transferred = 450 000 J

Power is given by work done per unit time. So,

$P=\dfrac{W}{t}\\\\t=\dfrac{W}{P}\\\\t=\dfrac{450 000}{1.5\times 10^3}\\\\t=300\ s$

So, it will take 300 seconds for the motor.

3 0

3 years ago