Lesson 2.12 • NIE Practical Handbook (Practicals 2.1 – 2.5)Interactive Simulation

Practical Laboratory Investigations

Interactive virtual laboratory covering all 5 official NIE A/L Physics syllabus practicals for Unit 2: (1) Force Parallelogram & Triangle, (2) Principle of Moments & Metre Rule, (3) U-Tube Immiscible Liquids, (4) Hare’s Apparatus & Slope, (5) Loaded Test Tube Flotation.

Marking a lesson complete represents finishing your study of the topic; it does not denote tested mastery.

Learning Objectives

Execute virtual laboratory trials, tabulate experimental readings, and evaluate systematic uncertainties.
Perform least-squares linear slope analysis in Hare’s apparatus and loaded hydrometer flotation experiments.
Generate printable laboratory record sheets with percentage discrepancy calculations.

Core Theory & Concepts

Laboratory practical work is essential for mastering physics. This interactive laboratory provides hands-on simulated environments for all 5 official NIE Grade 12 Mechanics practicals, complete with dynamic schematics, interactive data entry tables, linear regression plots, and printable records.

Practical 1: Gravesande Board

Verify F_diag = √(P² + Q² + 2PQ cos θ) ≈ R. Eliminate pulley axle friction by gentle tapping; eliminate parallax using a plane mirror strip.

Practical 2: Principle of Moments

Balance metre rule on knife edge. m_1 · (x_f - x_1) = M_rule · (50 - x_f). Verify across multiple fulcrum positions.

Practical 3: U-Tube Immiscible Liquids

Hydrostatic pressure balance at horizontal datum plane through the interface: h_L · ρ_L = h_w · ρ_w ⇒ RD = h_w / h_L.

Practical 4: Hare’s Apparatus

Plot water height h_w vs liquid height h_L: straight line through origin with slope m = ρ_L / ρ_w. Liquids remain isolated in separate beakers.

Practical 5: Loaded Test Tube Hydrometer

Total mass M vs immersion depth h: M = (A · ρ) · h. Slope m = A · ρ. External area A = π(d/2)².

Syllabus Topic Outline

NIE Practical Handbook (Practicals 2.1 – 2.5)

1Practical 1: Verification of Force Parallelogram & Triangle Laws on Gravesande board
2Practical 2: Principle of Moments & determination of Metre Rule mass
3Practical 3: U-Tube determination of Relative Density of an immiscible liquid
4Practical 4: Hare’s Apparatus determination of Relative Density via linear graph slope
5Practical 5: Principle of Flotation & Loaded Test Tube Hydrometer

A/L Physics Laboratory: Unit 2 Mechanics Practicals Hub

Interactive virtual laboratory investigations covering all 5 official NIE A/L Physics syllabus practicals for Unit 2 Mechanics.

Practical 5: Verification of the Parallelogram Law & Triangle of Forces

Aim: To verify the Parallelogram Law of Forces and Triangle of Forces for three coplanar concurrent forces in static equilibrium using Gravesande’s force board.

Apparatus: Gravesande’s force board, two frictionless pulleys, three slotted weight hangers with weights (P, Q, R), thin light cord, drawing paper, mirror strip, protractor, set squares.

Physical Principle & Parallelogram Geometry

When three coplanar concurrent forces P, Q, and R act on a knot in equilibrium, the vector sum is zero: P + Q + R = 0. According to the Parallelogram Law, the resultant of P and Q is represented in magnitude and direction by the diagonal of the parallelogram whose adjacent sides represent P and Q. For equilibrium, this diagonal resultant F_diag must be equal in magnitude and collinear in opposite direction to counterweight R: F_diag = √(P² + Q² + 2PQ cos θ) ≈ R.

Procedure: 1. Fix drawing paper to the vertical force board. 2. Pass strings over pulleys and suspend weights P and Q; suspend weight R from central knot O. 3. Adjust weights so knot O settles freely near the board center without touching the board or pulleys. 4. Using a mirror strip to eliminate parallax, mark the line of each thread with two pricks. 5. Measure angle θ between strings P and Q. 6. Draw vectors to scale and calculate the diagonal resultant.

Equilibrium Force Observations

Force P (g wt):

Force Q (g wt):

Counterweight R (g wt):

Angle θ between P and Q (°):

Analytical Resultant & Error Analysis

Calculated Diagonal Resultant:500 g wt

Measured Balancing Weight R:500 g wt

Percentage Discrepancy:0%

Equilibrium Verified (Discrepancy ≤ 5%)

Experimental Precautions

1. Tap the force board gently before reading to minimize pulley axle friction. 2. Use a plane mirror strip under strings to avoid parallax error when marking lines. 3. Ensure the central knot O does not rub against the drawing paper or board surface.