Before You Begin
Question #42054
The Question
A block of mass is attached to a light spring of force constant on a rough horizontal surface. The coefficients of static and kinetic friction are both . The block is pulled to a position from the spring's natural length () and released from rest. Let be the magnitude of the block's acceleration immediately before it reaches its first turning point (instantaneous rest), and be the magnitude of its acceleration immediately after it reverses direction. What is the value of the ratio ? (Take )
Options
- A.
- B.
- C.
- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Intuition_Breaker
Train your brain to resist "obvious" answers that are designed to deceive your intuition.
Concepts Behind This Question
Turning Point Identification|Kinetic Friction Transition|Work-Energy Theorem
Why This Question Is Tricky
Common Mistakes
This question tests the path-dependence of non-conservative forces and the resulting discontinuity in acceleration at turning points.
Students often incorrectly assume energy conservation without accounting for the work done by friction, leading to a wrong turning point ().
Furthermore, they must recognize that kinetic friction abruptly changes direction when the velocity vector flips at , causing a step-change in the net force and acceleration.
Failing to account for this transition leads to incorrect acceleration ratios.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Motion in a Straight Line - Class 11 Part 1 |
| Concept | Turning Point Identification |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |