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Lyrx [107]
3 years ago
9

A runner is training and runs past meter mark 65 and starts a stopwatch. After the runner passes meter mark 15 the stopwatch sto

ps at 8 seconds.
What was the runners velocity?
Question options:
-6.25 m/s
6.25 m/s
8.13 m/s
-1.88 m/s
Physics
1 answer:
denis-greek [22]3 years ago
7 0

Answer:

6.25 m/s

Explanation:

Given parameters

Initial mark = 65

Final mark  = 15

time taken = 8s

Unknown:

Velocity of the runner  = ?

Solution:

Velocity is the displacement divided by time;

        Velocity  = \frac{displacement}{time}  

Displacement  = Initial mark - final mark  = 65 - 15 = 50m

Now, insert the parameters and solve;

       Velocity  = \frac{50}{8}   = 6.25m/s

You might be interested in
A transverse wave on a long horizontal rope with a
frosja888 [35]

Answer:

2 seconds

Explanation:

The frequency of a wave is related to its wavelength and  speed by the equation

f=\frac{v}{\lambda}

where

f is the frequency

v is the speed of the wave

\lambda is the wavelength

For the wave in this problem,

v = 2 m/s

\lambda=8 m

So the frequency is

f=\frac{2}{8}=0.25 Hz

The period of a wave is equal to the reciprocal of the frequency, so for this wave:

T=\frac{1}{f}=\frac{1}{0.25}=4 s

This means that the wave takes 4 seconds to complete one full cycle.

Therefore, the time taken for the wave to go from a point with displacement +A to a point with displacement -A is half the period, therefore for this wave:

t=\frac{T}{2}=\frac{4}{2}=2 s

4 0
3 years ago
Two cars are moving towards each other and sound emitted by first car with real frequency of 3000 hertz is detected by a person
sertanlavr [38]

Answer:

 v ’= 21.44 m / s

Explanation:

This is a doppler effect exercise that changes the frequency of the sound due to the relative movement of the source and the observer, the expression that describes the phenomenon for body approaching s

           f ’= f (v + v₀) / (v-v_{s})

where it goes is the speed of sound 343 m / s, v_{s} the speed of the source v or the speed of the observer

in this exercise both the source and the observer are moving, we will assume that both have the same speed,

                v₀ = v_{s} = v ’

we substitute

               f ’= f (v + v’) / (v - v ’)

               f ’/ f (v-v’) = v + v ’

               v (f ’/ f -1) = v’ (1 + f ’/ f)

               v ’= (f’ / f-1) / (1 + f ’/ f) v

               v ’= (f’-f) / (f + f’) v

let's calculate

                v ’= (3400 -3000) / (3000 +3400) 343

                v ’= 400/6400 343

                v ’= 21.44 m / s

3 0
3 years ago
The US government wants to allocate billions of dollars in the next 10 years to help assure our future energy security. The fund
Tom [10]

This question is a very good one indeed! I am very happy you asked it. I would first like to say that, although energy is important, our planet is more so. That is why I feel like we should always try to explore ideas that are both useful to the human race but also useful in protecting our environment because what is the use in having energy if we will not be able to use it. That is why I feel that we should try at types of energy like solar and wind. The problem is finding ways that are less expensive and more efficient. For example, creating a wind energy system that creates a sizeable about of energy and also is not too expensive and hard to make like the wind turbines of nowadays. Also what comes into question is the effect of these ideas and I feel that although some of these may have harmful effects, they must be used. One thing though is that I do not agree in expanding on our oil and gas exploration because it has so many bad effects to our environment that it is hardly worth it. If we can find alternatives in these other sources, like many states in the USA are trying to do, then we will be able to move much faster in technology and also help protect our lovely planet.

7 0
3 years ago
(4.56 x 10^-13)-(1.17 x 10^-13)
avanturin [10]
3.39 x 10^-13

Please mark brainliest!
3 0
3 years ago
NUUS
Ne4ueva [31]
The answer would be Conduction
4 0
3 years ago
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