Question

Question #3d192

Answer 1

Given a car is driven on a straight line. Its distance `x` from a traffic light at red, starting point at `t=0`; is given as a function of time `t`
`x(t)=2t^2+0.25t^3`

First step: lets find `x(0), x(2) and x(4)`
`x(0)=2xx0^2+0.25xx0^3=0m`
`x(2)=2xx2^2+0.25xx2^3=8+2=10m`
`x(4)=2xx4^2+0.25xx4^3=32+16=48m`
We know that `"Average Velocity"=("Displacement " Delta x)/("Time of travel "Delta t)`
1. `t = 0 s` to `t = 2 s`
`"Average Velocity"=(x(2)-x(0))/(2-0)=(10-0)/(2)=5ms^-1`
2. `t = 2 s` to `t = 4 s`
`"Average Velocity"=(x(4)-x(2))/(4-2)=(48-10)/(2)=19ms^-1`
3. `t = 0 s` to `t = 4 s`
`"Average Velocity"=(x(4)-x(0))/(4-0)=(48-0)/(4)=12ms^-1`