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Yakvenalex [24]
2 years ago
8

A car slows down from speed of 72

Physics
1 answer:
Nastasia [14]2 years ago
5 0

Explanation:

Given parameters:

Initial velocity = 72km/hr

Final velocity  = 0km/hr

Time taken  = 25s

Unknown:

Acceleration = ?

Solution:

To solve this problem, convert km/hr to m/s;

           1000m = 1km

           3600s = 1hr

  72km/hr;

          1km/hr  = 0.278m/s

         72km/hr = 0.278 x 72  = 20.02m/s

Acceleration is the change in velocity divided by the time taken;

       Acceleration = \frac{final velocity - initial velocity }{time}  

       Acceleration  = \frac{0 - 20.02}{25}   = -0.8m/s

The car  is actually decelerating at a rate of 0.8m/s

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Answer:

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Explanation:

Given that,

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v=\dfrac{18.288}{2}

v=10\ m/sduring that run

(b). We need to calculate their velocity

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Put the value into the formula

v=\dfrac{22.86-36.58}{2}

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Negative sign shows the direction of motion.

(c). If they kept running at that velocity for another 1.3 seconds,

We need to calculate the final position

Using formula of position

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d=6.86\times1.3

d=8.91\ m

Hence, (a). Their speed during that run is 10 m/s.

(b). Their velocity is 6.86 m/s

(c). The final position is at 8.91 m.

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