# 7. A baseball player runs from home plate to first base, a distance of 90 feet.

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7. A baseball player runs from home plate to first base, a distance of 90 feet.The graph shows the displacement of the player over time. https://tcan4424-oakcliff-ccl.gradpoint.com/Resour...

What is the approximate average speed of the player's run to first base?

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8. Over a span of 6.0 seconds, a car changes its speed from 89 km/h to 37 km/h. What is its average acceleration in meters per second squared (m/s2)?

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May 17th, 2015

Hello!

7. The approximate average speed (distance traveled/time) will be in the units of feet/second (ft/sec)

You are given that the distance traveled is 90 feet.  From the graph, you can see that the baseball player has traveled 90 feet in roughly 4.75 seconds (time when line hits 90 feet).

Average speed = distance traveled/time

Avg speed = 90 ft / 4.75 sec

Avg speed = 18.9 ft/sec (approximate)

8. Average acceleration is in units of (m/s2).

Acceleration is how fast the car speeds up or slows down.  You can determine the change in velocity per a given time period to determine acceleration.

Average acceleration = change in velocity / time

change in velocity = Vfinal - Vinitial = 37km/h - 89km/h = -52km/h

But, you must convert this to m/s:

change in velocity = -52km/h * (1000m/1km) * (1h/60min) * (1min/60sec) = -14.4 m/s

Now plug this into the average acceleration equation:

Average acceleration = (-14.4m/s) / (6.0s) = -2.4s

A negative acceleration indicates that the car is slowing down.

Hope this helps!  Let me know if you have any question! :)

May 17th, 2015

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May 17th, 2015
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May 17th, 2015
Nov 20th, 2017
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