Question

Halfway though a cross-country meet,a runner’s speed is 4m/s.In the last stretch,she increases her speed to 7m/s.What is her change in speed?

Answer 1

v0=4 m/s
v1=7 m/s

Change in speed: v1-v0=7-4=3 m/s

Answer 2

The change in speed is 3m/s

Step-by-step explanation:

The change is speed is defined as the difference between final and initial speed:

ΔV=
`V_(2)-V_(1)`

where V2 and V1 are the final and initial speeds, respectively.

Plugging in the values

ΔV=7m/s-4m/s=3m/s