Let's break down the problem step by step: --- ## **Step 1: Understanding the Problem** **Given:** - A rear-wheel-drive car starts from rest and accelerates to the left. - The tires do not slip on the road. - **Question:** What is the direction of the acceleration of the point on the tire that is in contact with the road (point A)? --- ## **Step 2: Analyzing the Situation** - The car accelerates to the left (let’s call that the negative x-direction). - The rear wheels are driving the car (rear-wheel-drive). - The point of contact (A) is **momentarily at rest** with respect to the road because the tires do not slip. --- ## **Step 3: Forces and Accelerations on the Tire** ### **a. Translational Acceleration** - The center of mass of the car (and thus the wheel) is accelerating to the left. ### **b. Rotational Motion** - Since the car is accelerating to the left, the rear wheels are rotating **counterclockwise** (as seen from the left side of the car). - At point A (the contact point), the velocity is zero (no slip), but it still **accelerates**. ### **c. Acceleration at Point A** The acceleration of point A is the vector sum of: 1. The acceleration of the center of the wheel (to the left, same as the car's acceleration). 2. The rotational acceleration due to the wheel’s rotation (relative to the wheel’s center). #### **Relative Acceleration at Point A** - For a rolling wheel, the acceleration at the contact point (A) is \( 2a \) (where \( a \) is the acceleration of the center of mass), directed **forward** (to the left), relative to the ground. --- ## **Step 4: Direction of Acceleration** - Look at the options. The correct direction should be **to the left and slightly upward** (since it’s the vector sum of the linear and rotational components). However, in the context of most physics problems (and based on the choices), **the direction of acceleration of the contact point is to the left** (same as the acceleration of the car). --- ## **Step 5: Matching to the Choices** Let's decode the options: - a. Left and downward (\) - b. Left (←) - c. Left and upward (/) - d. Up (↑) - e. Down (↓) The correct answer is **b. Left (←)**. --- ## **Step 6: Final Answer** ### **Explanation** - The point of contact on the tire (A) is momentarily at rest with respect to the ground. - Its acceleration is the same as the acceleration of the car (to the left). - Thus, the direction of the acceleration is **to the left**. ### **Final Answer** **b. ← (Left)** --- **Summary:** When a rear-wheel-drive car accelerates to the left without slipping, the acceleration of the contact point of the tire with the road is to the left (same as the car's acceleration).