Math

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Someone verify if this is correct, please!

1. Draw a distance versus time graph that corresponds to the walk described below.

Adam starts 8 m away from the motion sensor and walks in a straight line toward the sensor at a constant rate of 0.5 m/s for 3 s. He immediately begins walking away from the sensor at a constant rate of 0.25 m/s for 4s. He stops for 1s and then walks toward the sensor at a constant rate of 0.5 m/s for 2 s.

Image is here imgur dot com/aKwAy

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2.
During what interval of time was the greatest distance travelled?

a) 0<t<5
b) 5<t<7
c) 7<t<10
d) cannot be determined

I don't which one is correct, 0<t<5 or 5<t<7

here is the image:

imgur dot com/vOojV

Thank yhou~

• Math - ,

For (1), the x-coordinates are plotted correctly. You will need to review the y-coordinates, because they do not seem to correspond with the ones given in the question.

The starting point of 8 m is correct.
Walking towards the sensor makes a line with negative slope is correct also.
The rate is 0.5m/sec., so over 3 seconds, he would have been closer by 3*0.5=1.5m.
So at the end of 3 seconds, he would be at a distance of 8-1.5=6.5 m from the sensor.
Proceed this way for the rest of the question and see if you arrive at 6.5 m at the end of the 10 seconds.

(2) You'd need to interpret the graph where the y-axis represents speed given by m/s.
Interval, speed
0-5 3m/s
5-7 4m/s
7-10 1m/s
Since distance = speed * time, you can calculate the distance covered in each interval and the interval with the greatest distance travelled is the right answer.

• Math - ,

Got it! THank you~~~~~~~

• Math :) - ,

Great! You're welcome!