Question

How long does it take an automobile traveling in the left lane of a highway at 60.0 km/h to overtake (become even with) another car that is traveling in the right lane at 20.0 km/h when the cars' front bumpers are initially 55 m apart?

Answer 1

Answer:

4.95 seconds

Explanation:

It is given that the speed of the cars are constant and not accelerating

The relative speed between the two cars will be the difference in their speeds

$S_r=60-20\\\Rightarrow S_r=40\ km/h$

Converting to m/s

$1\ km/h=\frac{1}{3.6}\ m/s$

$\\\Rightarrow 40\ km/h=40\times \frac{1}{3.6}\ m/s\\ =\frac{100}{9}\ m/s\\ =11.11\ m/s$

Time = Distance / Speed

$Time=\frac{55}{\frac{100}{9}}=4.95\ seconds$

Time it would take the faster car to cross the slower car is 4.95 seconds