Test Result — Physics Topic Test #5
Completed: 06 Apr 2026, 11:42 AM | Duration: 1 hour | Chapters: Mechanics (Newton's Laws, Work-Energy)
21 / 30
Questions Correct
Section Breakdown
| Section | Questions | Attempted | Correct | Wrong | Marks | Accuracy |
|---|
| Section A — MCQ | 25 | 24 | 18 | 6 | 66 | 75% |
| Section B — Numerical | 5 | 4 | 3 | 1 | −3 + 12 = 9 → wait, +4×3 −1×1 = 11 | 75% |
Mistake Classification
Time Analysis
| Metric | Value |
|---|
| Avg time per question | 94 seconds |
| Fastest question | Q3 — 18 seconds (FBD easy) |
| Slowest question | Q17 — 4 min 12 sec (Non-inertial frame, Hard) |
| Questions > 3 min | Q17, Q22, Q28 |
| Questions < 30 sec | Q1, Q3, Q6, Q9 |
| Unattempted | Q25, Q30 |
Topics Needing Attention (this test)
| Topic | Questions | Correct | Accuracy | Action |
|---|
| Non-inertial frames (pseudo force) | 3 | 0 | 0% | Practice Revise |
| Pulley systems with constraints | 4 | 2 | 50% | Practice |
| Inclined plane with friction | 5 | 3 | 60% | Practice |
| FBD on horizontal | 8 | 7 | 87% | — |
All Questions
Wrong Only (7)
Marked for Review (2)
Question-wise Review
A block of mass 5 kg is placed on a rough horizontal surface (μk = 0.3). A force of 25 N is applied at 30° above horizontal. Find acceleration. (g = 10 m/s²)
Your answer: (B) 2.46 m/s²
Correct answer: (A) 1.83 m/s²
Error: Normal force was miscalculated — you used N = mg, but the applied force has a vertical (upward) component that reduces N. N = mg − F·sin30° = 37.5 N, not 50 N.
Your Approach:
Resolving force components: F_x = 25 cos30 = 21.65 N, F_y = 25 sin30 = 12.5 N (upward).
Normal force: N = mg - F_y = 50 - 12.5 = 37.5 N.
Friction: f = 0.3 × 37.5 = 11.25 N (opposing motion).
Net force = 21.65 - 11.25 = 10.4 N.
a = 10.4 / 5 = 2.08 m/s² → closest to option B.
Two blocks of mass 3 kg and 5 kg are connected by a light string over a frictionless pulley. Find the acceleration of the system and tension in the string. (g = 10 m/s²)
Your answer: (C) a = 2.5 m/s², T = 37.5 N
Correct answer: (C) a = 2.5 m/s², T = 37.5 N
Your Approach:
Using Atwood formula: a = (m2-m1)g/(m1+m2) = (5-3)×10/8 = 2.5 m/s².
Tension: T = m1(g+a) = 3×12.5 = 37.5 N. Cross-check: T = m2(g-a) = 5×7.5 = 37.5 ✓.
Marked for review because I want to double-check the tension formula direction.
A person of mass 60 kg is in an elevator accelerating upward at 2 m/s². Find the normal force exerted by the floor on the person. (g = 10 m/s²)
Your answer: (A) 600 N
Correct answer: (C) 720 N
Error: Did not account for net upward acceleration. N = m(g + a) = 60×12 = 720 N, not just mg.
Your Approach:
Person is in elevator. Weight = mg = 600 N. Normal force = weight = 600 N.
(Did not apply Newton's 2nd law correctly in non-inertial frame context)