Question

A car going 50mph accelerates to pass a truck. Five seconds later the car is going 80mph. Calculate the acceleration of the car.

Answer 1

The answer to the question will be $21,600\ miles/hour^2$

CALCULATION:

The initial velocity of the car is given as u = 50 mph.

The final velocity of the car is given as v = 80 mph.

The time taken by the car to reach the velocity of 80 mph from 50 mph is given as t = 5 seconds.

We know one hour = 3600 seconds

                 one second = $\frac{1}{3600}\ hour$

                 5 seconds = $5\times \frac{1}{3600}\ hour$

We are asked to calculate the acceleration of the car.

Let the acceleration of the car is denoted as a.

From equation of kinematics, we know that -

                             $v=u+at$

                            ⇒ $80\ mph=50\ mph+\frac{5}{3600}a$

                           ⇒  $\frac{5}{3600}a=30$

                             ⇒$a=\frac{3600}{5}\times 30$

                            ⇒ $a=\ 21,600\ miles/hour^2$   [ans]