Question

A train and a car are traveling in the same direction with velocities 40 km/h and 60 km/h. The change in the distance of separation after two hours is: a) 40 km b) 200 km c) 120 km d) 80 km

Answer 1

The change in the distance of separation between the train and the car after two hours is 40 km, calculated using their relative velocity of 20 km/h over a period of 2 hours.

Step-by-step explanation:

The question asks for the change in distance of separation between a train and a car after two hours when they are moving in the same direction at different velocities. The train is moving at 40 km/h and the car at 60 km/h. To find the change in their distance of separation, we need to calculate the relative velocity between the two. The relative velocity is the difference in their speeds because they are moving in the same direction. Therefore, the relative velocity is 60 km/h - 40 km/h = 20 km/h. Over a period of 2 hours, the change in distance of separation is distance = velocity × time, which gives us:

Distance = 20 km/h × 2 h = 40 km.

This means that after two hours, the car will be 40 kilometers further away from the train than it was at the start.

Answer 2

The change in the distance of separation can be found by subtracting the initial distance between the train and the car from the final distance after two hours. The correct answer is option a) 40 km.

Step-by-step explanation:

The change in the distance of separation can be found by subtracting the initial distance between the train and the car from the final distance after two hours. Since the train and the car are traveling in the same direction, the distance between them will be decreasing over time.

The train's velocity is 40 km/h and it travels for 2 hours, so the distance it covers is 40 km/h * 2 h = 80 km.

The car's velocity is 60 km/h and it travels for 2 hours, so the distance it covers is 60 km/h * 2 h = 120 km.

Therefore, the change in the distance of separation after two hours is 120 km - 80 km = 40 km. So the correct answer is option a) 40 km.