All categories

3 years ago

What is the most appropriate SI unit to express the speed of a cyclist in a 10-km race? km/s cm/h km/h mm/s

1 answer:

5 0

You sure wouldn't want something like cm/s or (yikes cm/hr). You want a reasonable number for sports usually between 0 and 100

Km / hour would be a good choice.

The next town to where I live is 25 km away. On a good day, I can make it there in about 3/4 of an hour.

Speed = 25 km / 0.75 hour = 33.3 km/hour. That's actually a little fast most of the time. But you should understand what I mean.

You might be interested in

For a given wave if the frequency doubles the wave length?

pav-90 [236]

For a given wave in a given medium, if the frequency doubles,
the wavelength becomes 50% shorter.

That is, it becomes half as long as it was originally.

5 0

2 years ago

A 65 kilogram astronaut weighs 638 newtons at the surface of earth what is the mass of the astronaut at the surface of the moon,

Montano1993 [528]

The mass of the astronaut is still 65 kilograms. Mass is constant or doesn't change no matter where you are.

3 0

3 years ago

Read 2 more answers

A commuter train passes a passenger platform at a constant speed of 39.6 m/s. The train horn is sounded at its characteristic fr

Licemer1 [7]

Complete Question

A commuter train passes a passenger platform at a constant speed of 39.6 m/s. The train horn is sounded at its characteristic frequency of 350 Hz.

(a)

What overall change in frequency is detected by a person on the platform as the train moves from approaching to receding

(b) What wavelength is detected by a person on the platform as the train approaches?

Answer:

$\Delta f = 81.93 \ Hz$

$\lambda_1 = 0.867 \ m$

Explanation:

From the question we are told that

The speed of the train is $v_t = 39.6 m/s$

The frequency of the train horn is $f_t = 350 \ Hz$

Generally the speed of sound has a constant values of $v_s = 343 m/s$

Now according to dopplers equation when the train(source) approaches a person on the platform(observe) then the frequency on the sound observed by the observer can be mathematically represented as

$f_1 = f * \frac{v_s}{v_s - v_t}$

substituting values

$f_1 = 350 * \frac{343 }{343-39.6}$

$f_1 = 395.7 \ Hz$

Now according to dopplers equation when the train(source) moves away from the person on the platform(observe) then the frequency on the sound observed by the observer can be mathematically represented as

$f_2 = f * \frac{v_s}{v_s +v_t}$

substituting values

$f_2 = 350 * \frac{343}{343 + 39.6}$

$f_2 = 313.77 \ Hz$

The overall change in frequency is detected by a person on the platform as the train moves from approaching to receding is mathematically evaluated as

$\Delta f = f_1 - f_2$

$\Delta f = 395.7 - 313.77$

$\Delta f = 81.93 \ Hz$

Generally the wavelength detected by the person as the train approaches is mathematically represented as

$\lambda_1 = \frac{v}{f_1 }$

$\lambda_1 = \frac{343}{395.7 }$

$\lambda_1 = 0.867 \ m$

4 0

3 years ago

A wire that is 0.86 meters long is moved perpendicularly through a constant magnetic field of strength 0.035 newtons/amp·meter a

GaryK [48]

The emf induced = B*l*v where B is the flux density, l the length of the conductor and v the velocity of the conductor. In the given case B = 0.035 N/amp.meter, l = 0.86 and v = 6 m/sec
emf = 0.035*0.86*6 = 0.1806 v ≈ 0.18 v
choice: D

6 0

2 years ago

laser light sent through a double slit produces an interference pattern on a screen 3.0 m from the slits. If the eighth order ma

Xelga [282]

Solution :

Given the laser light which is sent through the double slit produces an interference pattern on the screen placed 3 meters from the slits.

The 8th order maximum occurs at angle = 12

So,

$8^{th} \text{ order maxima} = d \sin \theta = m \lambda$ , m = 8