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2 years ago

during a crash, the acceleration was less than 30g. Calculate the force on a 70 kg person accelerating at this rate.

Physics

1 answer:

Igoryamba2 years ago

4 0

Answer:

less than 20580 N

Explanation:

According to the newton's second law of motion

Force = mass * acceleration

(assuming gravitational acceleration =9.8 m/s2 )

acceleration = 30*9.8 = 294 m/s2

acting Force = 70 * 294

= 20580 N

Since the acceleration was less than 30g , acting force should also be less than 20580 N

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A trombone plays a C3 note. If the speed of sound in air is 343 m/s and the wavelength of this note is

Umnica [9.8K]

The frequency of note C3 is 131 $s^{-1}$ .

<u>Explanation:</u>

Frequency is the measure of repetition of same thing a certain number of times. So frequency is inversely proportional to the wavelength. As wavelength is distance between two successive crests or troughs in a sound wave.

And frequency is the completion of number of cycles in a given time in sound waves. The frequency and wavelength are inversely proportional to each other with velocity of sound being the proportionality constant.

Thus, here the speed of sound is given as 343 m/s, the wavelength of the note is also given as 2.62 m, then frequency will be as follows:

$Frequency=\frac{speed of sound}{Wavelength of note}$

Thus,

$Frequency = \frac{343 m/s}{2.62 m} = 131 s^{-1}$

So the frequency of note C3 is 131 $s^{-1}$ .

3 0

2 years ago

Rahul wants to change the motion map shown so that it shows uniform circular motion. What change should Rahul make?

saw5 [17]

Answer:

B. He should change the lengths of the vectors that point tangent to the circle so that each is the same length.

Explanation:

A uniform circular motion is a motion in a circle where the tangential speed of the object is constant.

In the motion map:

- The arrows pointing towards the centre of the circle represent the centripetal acceleration, and their length represent the magnitude of the acceleration

- The arrows pointing tangential to the circle represent the tangential speed, and their length represent the magnitude of the speed

In this motion map, we see that the length of the vectors pointing tangent to the circle is not constant: this means that the speed is not constant. In order to have a uniform circular motion, the speed must be constant, therefore the lengths of the vectors that point tangent to the circle must be the same.

6 0

3 years ago

Read 2 more answers

A body of mass 2.7 kg makes an elastic collision with another body at rest and continues to move in the original direction but w

kramer

Answer:

1.35 kg

2.67 ms⁻¹

Explanation:

$m_{1}$ = mass of first body = 2.7 kg

$m_{2}$ = mass of second body = ?

$v_{1i}$ = initial velocity of the first body before collision = $v$

$v_{2i}$ = initial velocity of the second body before collision = 0 m/s

$v_{1f}$ = final velocity of the first body after collision =

using conservation of momentum equation

$m_{1} v_{1i} + m_{2} v_{2i} = m_{1} v_{1f} + m_{2} v_{2f}\\(2.7) v + m_{2} (0) = (2.7) (\frac{v}{3} ) + m_{2} v_{2f}\\(2.7) (\frac{2v}{3} ) = m_{2} v_{2f}\\v_{2f} = \frac{1.8v}{m_{2}}$

Using conservation of kinetic energy

$m_{1} v_{1i}^{2}+ m_{2} v_{2i}^{2} = m_{1} v_{1f}^{2} + m_{2} v_{2f}^{2} \\(2.7) v^{2} + m_{2} (0)^{2} = (2.7) (\frac{v}{3} )^{2} + m_{2} (\frac{1.8v}{m_{2}})^{2} \\(2.7) = (0.3) + \frac{3.24}{m_{2}}\\m_{2} = 1.35$