Question

A dancer is demonstrating dance steps along a straight line. The position-time graph is given above. Find the average velocity of the dancer during the time interval between $t=4.5s$ to $t=9s$.

• A. $1m{s}^{-1}$
• B. $-1.33m{s}^{-1}$
• C. $2.75m{s}^{-1}$
• D. $-0.89m{s}^{-1}$

Answer 1

Answer: (D)

$-0.89m{s}^{-1}$

Between $t=4.5s$ to $t=9s$,

Initial position $x_i=4m$

Final position $x_f=0m$

Displacement $S=x_f-x_i=0-4=-4m$

Time $t=9-4.5=4.5s$

Average velocity $V_{avg}=\frac{S}{t}=\frac{-4}{4.5}=-0.89m/s$