The velocity-time graph of a bosy moving along a straight line is given bellow dind:
Average velocity in whole time of motion
(b) Average speed in whole time of motion
(c ) Draw acceleration vs time graph.
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Explanation

a. Area of graph above time axis
`A=(1)/(2)xx(8+4)xx=60 m`
Area of graph below time axis
`B=(1)/(2)xx4=10=20 m`
Average velocity in whole time of motion
`vec v=(Displacement)/(Total time )`
`=(Area A-Area B)/(Total time) =(600-20)/(12) =3.33 m s^(-1)`
b. Averaga speed in whole time of motion
`v_(av)=(Total Area B)/(Total time)`
`=(Area A + Area B)/(Totla time) =(60+20)/(12) =6.67 m s^(-1)`
c. Acceleration:
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From `0` to `2 s`,
`a(v_(2)-v_(1))/(t_(2)-t_(1))=(10-0)/(2-0) =5 m s^(-2)`
From `2` to `6 s`, `a=(v_(2)-v_(1))/(t_(2)-t_(1))=(10-10)/(6-2)=0`
From `6` to `10 s`, `a=(v_(2)-v_(1))/(t_(2)-t_(1))=(10-10)/(10-2)=5 m s^(-2)`
From `10` to `12` s,
`a=(v_(2)-v_(1))/(t_(2)-t_(1))=(0-(-10))/(12-10)= 5 m s^(-2)`
Acceleration vs time graph is drawn in .