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3 years ago

A man walks 7 km East in 2 hours and then 2.5 km West in 1 hour. What is

Physics

1 answer:

madam [21]3 years ago

6 0

<h2><u>How</u><u> </u><u>to</u><u> </u><u>solve</u><u>?</u></h2>

We know that, Velocity is the rate of displacement covered. Displacement is the shortest path between the Initial and Final point covered by the body. So,

Velocity = Displacement / Time

And, when it comes to Average velocity, It is the total displacement by total time taken. So, By using this let's solve this question.....

<h2><u>Solution</u><u>:</u></h2>

✏️ Refer to the attachment...

Let the body goes to point A that is 7 m East of the Initial point. Then it comes backward because West is opposite to East in perpendicular direction. It covers 1.5 m backwards in the same line to reach B which is the Final point.

So,

Displacement = Final point - Initial point

⇛ Displacement = 7 m - 1.5 m

⇛ Displacement = 5.5 m

Total time taken,

⇛ 2 hours + 1 hour

⇛ 3 hours

Finding Average displacement,

⇛ Total displacement / Total time taken

⇛ 5.5 m / 3 hours

⇛ 1.83333.... hours

So, the Final answer is,

$\huge{ \boxed{ \bold{ \purple{1.8 \bar{3}m}}}}$

<u>━━━━━━━━━━━━━━━━━━━━</u>

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James rode his bike 0.65 hours and traveled 8.45 km. What was his speed?

maria [59]

Speed = (distance covered) / (time to cover the distance)

= ( 8.45 km) / (0.65 hr)

= (8.45 / 0.65) km/hr

= 13 km/hr

5 0

3 years ago

Why a drop of spirit on the hand feels colder than a drop of water at the same temperature

brilliants [131]

Answer:

This is because spirit has a lower boiling point when compared to water

Explanation:

spirit has a lower boiling point when compared to water which means it has the capacity to pull more heat from your hand and also it can do this very fast. This is why our hand feels colder.

5 0

2 years ago

A carbon resistor is to be used as a thermometer. On a winter day when the temperature is 4.00°C, the resistance of the carbon r

dusya [7]

Answer:

28 degree C

Explanation:

We are given that

$T_1=4.00^{\circ}$

$R_1=217.7 \Ohm$

$R_2=215.1\Ohm$

$\alpha=-5.00\times 10^{-4}C^{-1}$

We have to find the temperature on a spring day when resistance is 215.1 ohm.

We know that

$\alpha(T_2-T_1)=\frac{R_2}{R_2}-1$

Using the formula

$-5.00\times 10^{-4}(T_2-4)=\frac{215.1}{217.7}-1$

$-5\times 10^{-4}(T_2-4)=0.988-1=-0.012$

$T_2-4=\frac{0.012}{5\times 10^{-4}}=24$

$T_2=24+4=28^{\circ}C$

Hence, the temperature on a spring day 28 degree C.

7 0

3 years ago

One string of a certain musical instrument is 70.0 cm long and has a mass of 8.79 g . It is being played in a room where the spe

Svetach [21]

To solve this problem we will apply the concepts of linear mass density, and the expression of the wavelength with which we can find the frequency of the string. With these values it will be possible to find the voltage value. Later we will apply concepts related to harmonic waves in order to find the fundamental frequency.

The linear mass density is given as,

$\mu = \frac{m}{l}$

$\mu = \frac{8.79*10^{-3}}{70*10^{-2}}$

$\mu = 0.01255kg/m$

The expression for the wavelength of the standing wave for the second overtone is

$\lambda = \frac{2}{3} l$

Replacing we have

$\lambda = \frac{2}{3} (70*10^{-2})$

$\lambda = 0.466m$

The frequency of the sound wave is

$f_s = \frac{v}{\lambda_s}$

$f_s = \frac{344}{0.768}$

$f_s = 448Hz$

Now the velocity of the wave would be

$v = f_s \lambda$

$v = (448)(0.466)$

$v = 208.768m/s$

The expression that relates the velocity of the wave, tension on the string and linear mass density is

$v = \sqrt{\frac{T}{\mu}}$

$v^2 = \frac{T}{\mu}$

$T= \mu v^2$

$T = (0.01255kg/m)(208.768m/s)^2$

$T = 547N$

The tension in the string is 547N

PART B) The relation between the fundamental frequency and the $n^{th}$ harmonic frequency is

$f_n = nf_1$

Overtone is the resonant frequency above the fundamental frequency. The second overtone is the second resonant frequency after the fundamental frequency. Therefore

$n=3$