Video Transcript
A car takes some time to travel from one end of a stretch of road to the other end. And the ends of the road are 540 metres apart. The car travels along the stretch of road at a constant speed of 36 metres per second. How much time does it take for the car to reach the other end?
So let’s start by underlining all the important information we’ve been given here. We know that a car is travelling along the road and the ends of the road are 540 metres apart from each other. In other words, the car is travelling 540 metres. Whilst it is travelling this 540 metres, the car is moving at a constant speed of 36 metres per second. What we’re asked to do is to find out how much time it takes the car to go from one end of the road to the other.
Now, the first thing we can do is to label all the quantities we’ve been given. The distance travelled is 𝑑, which is 540 metres. The speed is 𝑠, 36 metres per second. And we’re asked to find the time 𝑡.
To answer this question, we can recall that speed is defined as the rate of change of distance. In other words, speed is equal to distance over time or speed is the amount of distance travelled in every unit of time, which means that all we need to do is to take this equation and rearrange it to solve for the time.
So let’s do that. If we multiply both sides of the equation by the time divided by the speed, then we get that the time taken is equal to the distance divided by the speed. All we need to do now is to plug in our values and that gives us a time of 15 seconds. Therefore, a car travelling 540 metres at a speed of 36 metres per second takes 15 seconds to get there.
