To determine the average velocity of the car for the entire trip, we need to follow a systematic approach. Let's break it down step-by-step. ### Step 1: Understand the Concept of Average Velocity Average velocity is defined as the total displacement divided by the total time taken. Displacement is the straight-line distance from the starting point to the final position, along with the direction. ### Step 2: Calculate Total Displacement 1. **First Leg of the Trip:** - The car travels **150 kilometers north**. - Displacement for this leg = +150 km (we consider north as the positive direction). 2. **Second Leg of the Trip:** - The car then travels **50 kilometers south**. - Displacement for this leg = -50 km (south is considered the negative direction). 3. **Total Displacement:** \[ \text{Total Displacement} = 150 \text{ km (north)} - 50 \text{ km (south)} = 100 \text{ km (north)} \] ### Step 3: Calculate Total Time 1. **Time for the First Leg:** - The car takes **2 hours** to travel north. 2. **Time for the Second Leg:** - The car takes **1 hour** to travel south. 3. **Total Time:** \[ \text{Total Time} = 2 \text{ hours} + 1 \text{ hour} = 3 \text{ hours} \] ### Step 4: Calculate Average Velocity Now that we have both total displacement and total time, we can calculate the average velocity using the formula: \[ \text{Average Velocity} = \frac{\text{Total Displacement}}{\text{Total Time}} \] Substituting the values we calculated: \[ \text{Average Velocity} = \frac{100 \text{ km (north)}}{3 \text{ hours}} \approx 33.33 \text{ km/h (north)} \] ### Conclusion The average velocity of the car for the entire trip is approximately **33.33 km/h north**. Therefore, the correct option is **B**. ### Explanation of Other Options - **Option A: 50 km/h north** - This option incorrectly assumes that the average velocity is simply the total distance divided by total time without considering the direction of displacement. The total distance traveled is 200 km (150 km north + 50 km south), but average velocity depends on displacement, not distance. - **Option C: 25 km/h south** - This option is incorrect because it misinterprets the direction of the average velocity. The net displacement is north, not south, so the average velocity cannot be south. - **Option D: 100 km/h north** - This option is also incorrect as it miscalculates the average velocity. It seems to confuse average speed with average velocity. Average speed would be total distance divided by total time, which is 66.67 km/h, but that is not the same as average velocity. ### Revision Summary - Average velocity is calculated as total displacement divided by total time. - Displacement considers direction, while distance does not. - For this problem, total displacement was 100 km north, and total time was 3 hours. - The average velocity is approximately 33.33 km/h north, making option B the correct answer.