A person starst form a point O and travels along a path PQRP as shown in the figure. Then, the speed of the operson is __________ `m s^(-2)`

Options

A. `0.2`
B. 20
C. 12
D. `0.4`

Explanation

From the given figure, by Pythagorous theorm `PR^(2)=PQ^(2)+RQ^(2)`
`PR^(2)=4^(2)+3^(2)`
`PR^(2)=16+9`
`PR=sqrt(25)rArrPR=5m`
Average speed
`=("total distance")/("total time")=(4m+3m+5m)/(20s+10s+30s)`
`=(12m)/*(60s)=0.2 m s^(-1)`