# Acceleration equations involving time.

At highway speeds, a certain car is capable of an an acceleration of about 1.7 m/s^2. At this rate, how long does it take to accelerate from 90 km/hr to 110 km/hr? (WATCH UNITS.)

Given- Time=?
A=1.7m/s^2
Vi=90km/hr
Vf=110km/hr

Vf=vi+at Solve for t! T= vf-vi/a 110km/hr-90km/hr = 20km/hr
1.7m/s^2

How do I divide 20km/hr by 1.7 m/s^2?

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At highway speeds, a certain car is capable of an an acceleration of about 1.7 m/s^2. At this rate, how long does it take to accelerate from 90 km/hr to 110 km/hr? (WATCH UNITS.)

Given- Time=?
A=1.7m/s^2
Vi=90km/hr
Vf=110km/hr

Vf=vi+at Solve for t! T= vf-vi/a 110km/hr-90km/hr = 20km/hr
1.7m/s^2

How do I divide 20km/hr by 1.7 m/s^2?
First convert your units to be in terms of meters and seconds then do the calculation.

First convert your units to be in terms of meters and seconds then do the calculation.
I got .02m but i'm not sure how to convert the hr to seconds

I got .02m but i'm not sure how to convert the hr to seconds
What is that .02m?
You want to convert km/hr to m/s.An hour has 60 mins and a min has 60 sec.
$\frac{1km}{hr}\frac{1hr}{3600s}\frac{1000m}{1km}= \frac {1000m}{3600s}$

What is that .02m?
You want to convert km/hr to m/s.An hour has 60 mins and a min has 60 sec.
$\frac{1km}{hr}\frac{1hr}{3600s}\frac{1000m}{1km}= \frac {1000m}{3600s}$
What I did now was 20(1000)/3600
is 6m/s using sig figs and thats the answer! right?

What I did now was 20(1000)/3600
is 6m/s using sig figs and thats the answer! right?
Yes if your teacher requires you to round up after every step.I would round after the final answer for time though.