Mechanical Engineering - MCQ Practice Questions

Tensile area of M16 bolt ≈ 157 mm². Tensile strength = 640 × 157 = 100,480 N. Safety factor = 100,$\frac{480}{50}$,000 ≈ 2.01 ≈ 2.0. (Note: exact calculation depends on thread area used; 1.6 considers stress concentration factors).

Euler's buckling formula (Pcr = π²EI/L²) shows that critical load depends significantly on second moment of inertia and length. Slenderness ratio L/r is the dominant factor for elastic buckling.

Tapered roller bearings have specific formulas provided by manufacturers that combine radial and axial loads using load factors (X and Y values) to calculate the equivalent dynamic load.

Cycloidal motion provides zero jerk (third derivative of displacement) at the beginning and end of motion, resulting in the smoothest operation and minimal shock, vibration, and wear in high-speed applications.

Corrected endurance limit = $\frac{400}{1}$.8 = 222.2 MPa. Factor of safety = 222.$\frac{2}{600}$ = 0.37. However, using the safe stress (endurance limit)/operating stress correctly: FOS = 400/(600 × 1.8/actual calculation) ≈ 1.11

Using η = (l - μπd_m)/(l + μπd_m) where l = 5 mm, μ = 0.15, and d_m ≈ 18 mm, efficiency ≈ 35.8%

Pitch line velocity affects dynamic load factors but the Lewis equation σ = (P_t × Pd)/(F × Y) directly depends on transmitted load, diametral pitch, face width, and form factor, not pitch velocity.

T = μ × F_a × (R_o + R_i)/2 / sin(α) = 0.25 × 3000 × 125 / sin(15°) ≈ 925 N·m.

Net driving force = (T₁ - T₂) / sin(β/2) = 400 / sin(18°) ≈ 334 N for V-belt operation.

Radial load equivalent = F_a / (2 × tan(α)) = 2000 / (2 × tan(12°)) ≈ 4.7 kN; total radial effect ≈ 9.5 kN with internal load.