Can someone explain how to get these answers? ( Velocity/Acceleration Question)

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Need Explanation Please.

1 Answer
Feb 11, 2018

(a) Average acceleration ="Total change in velocity"/"Total time taken for the change"=Total change in velocityTotal time taken for the change
From the figure.
v_(x_(t=0))=0\ ms^-1
v_(x_(t=10.0))=4\ ms^-1

Inserting these values in above equation we get
Average acceleration =(4-0)/(10.0-0)=4/10=0.4\ ms^-2

(b) Maximum positive value of acceleration will occur when rate of change of velocity in increasing sense (slope of the velocity-time curve) is maximum positive. From the figure we see that this occurs at t=3\ s To find the value of this acceleration, draw a tangent to the curve at t=3. Calculate the slope of the curve using "Rise"/"Run".

(c) Acceleration is zero when rate of change of velocity is zero. Or the velocity-time graph becomes parallel to the x-axis. This happens at t=6\ s

(d) Maximum negative value of acceleration will occur when rate of change of velocity in decreasing sense (slope of the velocity-time curve) is maximum negative. From the figure we see that this occurs at t=8\ s To find the value of this acceleration, draw a tangent to the curve at t=8. Calculate the slope of the curve using "Rise"/"Run". In this case observe that rise is actually fall and is negative as value of velocity is falling. Therefore, slope will be negative.