Question

A car starts moving from a traffic light on a highway with a constant acceleration of 2.5 m/s^2. The speed limit is 65 miles/hour. Calculate the time from the start, when the car will exceed the speed limit, assuming that it keeps accelerating (in seconds).

Answer 1

Answer:

After 11.62 sec car will axceed the speed limit  

Explanation:

We have given constant acceleration $a=2.5m/sec^2$

As the car starts from rest so its initial velocity u = 0 m/sec

Final velocity v = 65 miles/hr

We know that 1 mile = 1609 meters

And 1 hour = 3600 sec

So $65miles/hour=\frac{65\times 1609m}{3600sec}=29.051m/sec$

From first equation of motion v = u+at

So $29.051=0+2.5\times t$

t = 11.62 sec

So after 11.62 sec car will axceed the speed limit