Since the velocity is not constant, solve for the average velocity.
Then, apply the formula:
where d - displacement and t - total time.
Hence, it took 7.5 seconds to travel 300ft with the given velocities.
the equation of motion are:
`s=s_0+at` and : `T=T_0+s_0t +1/2 at^2`
where s is speed, a acceleration and T the space.
(`s_0` and`T_0` are the initial speed and the initial sapce forom a system of coordinates. We further supposed the uniformly accelerated motion with a=costant)
so we have:
`at= s-s_0` (1)
We know both value `s-s_0= 60-20=40` than `T-T_0=300`
that is: `at=40` (3)
Substituing this in (2):
`T-T_0= s_0t+ 20t`
`300=20t+20t=40t` `t= 7,5sec`