Question

Two cars approach each other on a straight and level road. Car A is traveling at 75 km/h, due north and Car B is traveling at 45 km/h due south. Both velocities are measured relative to the ground. At a certain instant, the distance between the cars is 15 km. How long will it take, in seconds, from that instant for the two cars to meet?

Answer 1

The two cars will meet after 450 seconds.

Step-by-step explanation:

To solve this problem, we need to determine how long it will take for the two cars to meet. Since the cars are moving towards each other, we can add their velocities to find the relative velocity between them. Car A is moving at 75 km/h north, and Car B is moving at 45 km/h south. When we add these velocities, we get a relative velocity of 120 km/h.

Since the relative velocity is the rate at which the distance between the cars is decreasing, we can use the formula distance = rate × time to find the time it takes for the cars to meet. In this case, the distance is 15 km and the rate is 120 km/h. Plugging these values into the formula, we have:15 km = 120 km/h × time

Solving for time, we get:time = 15 km / 120 km/h = 0.125 hours

Since there are 60 minutes in an hour and 60 seconds in a minute, we can convert 0.125 hours to seconds:

0.125 hours × 60 minutes/hour × 60 seconds/minute = 450 seconds

Therefore, it will take 450 seconds for the two cars to meet.

Answer 2

it will take the cars t = 0.125 h for them to have a distance of 15 km between them.

Step-by-step explanation:

at the instant the cars are 15 km apart they gonna have to move:

75×t and 45×t respectively

where t is the time it will take them to be move until they 15 km apart,then to find the time:

75×t + 45×t = 15

120×t = 15

t = 0.125 h

Therefore, it will take the cars 0.125 hours for them to end up being 15 km apart.