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oksian1 [2.3K]
3 years ago
10

Brad is working on a speed problem in physics class. The problem tells him that a girl runs from her house to the park 0.05 km a

way in 10 s. Brad calculates that her speed is 0.005 m/s. Is he correct? If not, explain the flaw or flaws in his problem solving process.
Physics
2 answers:
Dmitriy789 [7]3 years ago
7 0
It is corecct becasue it 10 s more added from 0.05
Olegator [25]3 years ago
3 0

Answer:

He is incorrect!  Her speed was 5m/s.

Explanation:

For calculating the speed, first we shall remember that:

v=\dfrac{d}{t}

Where v is the speed, d is the distance travelled and, t is the time it takes to travel distance d.

So one migth think that velocity can be easely compute:

v=\dfrac{0.05}{10}

v=0.005\dfrac{m}{s}

Be carefull, he does not make a proper dimensional analisis!  

Before computing the speed we must know in what dimensions our values are.

d=0.05km, distances is measure in Kilometers.

t=10s, time is measure in seconds.

If we want our speed to be in m/s, first we need to be sure that our values are expressed  in meters and seconds.

Time is already  expressed in seconds, distance is not in Kilometers.

So

0.05Km=50m,

now we can compute the speed:

v=\dfrac{d}{t}

v=\dfrac{50m}{10s}

v=\5dfrac{m}{s}

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