Answer: \(12\text{ metre per seconds}\)
Step-by-step explanation:
Given equation: \(d(t)=0.8t^2\) , d(t), in meters, the rock travels after t seconds .
At t=5
The rock travels distance=\(d(5)=0.8(5)^2=0.8\times25=20\ m\)
At t=10
The rock travels distance=\(d(10)=0.8(10)^2=0.8\times100=80\ m\)
Total distance traveled by rock 5 and 10 seconds after it was dropped
=80-20=60 m
Total time =10-5=5 seconds
We know that the average speed =\(\frac{\text{Total distance}}{\text{Total time}}\)
\(=\frac{60}{5}=12\text{ meters per second}\)
