# Automotive Engine Components Design Questions and Answers – IC Engine – Whipping Stress

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This set of Automotive Engine Components Design Questions & Answers for Exams focuses on “IC Engine – Whipping Stress”.

1. The small end of connecting rod experience which motion?
a) Rotary motion
b) Circular motion
c) Epicyclic motion
d) Translation motion

Explanation: The small end of the connecting rod is subjected to pure translation motion while the big end is subjected to pure rotary motion. The translation motion is by piston.

2. The big end of connecting rod experience which motion?
a) linear motion
b) Reciprocating motion
c) Rotary motion
d) Epicyclic motion

Explanation: The big end of the connecting rod is subjected to pure rotary motion. This rotary motion is by the crankshaft, which is connected through a big end cap with bolts.

3. The intermediate points on the connecting rod move in which orbit?
a) Rectangular orbit
b) Circular orbit
c) Elliptical orbit
d) Triangular orbit

Explanation: The intermediate points on the connecting rod move in elliptical orbits. It is a special case of a circular orbit, with eccentricity equal to 0.

4. The bending stress due to inertia force is known as _________
a) Whipping stress
b) Axial stress
c) Shear stress
d) Angular stress

Explanation: The lateral oscillations of the connecting rod induce inertia forces that act all along the length of the connecting rod causing bending. This type of action is called whipping stress.

5. What is the formula for the mass of the connecting rod when l=1?
a) A=ρm
b) mi=Aρ
c) ρ=mlA
d) σ=mρ

Explanation: The Mass of the connecting rod is given by m1= volume ×density
m1= area ×length ×density
m1= A(1)(ρ)
m1= Aρ

6. Calculate the area of cross-section when the thickness of the web is 5mm?
a) 190mm2
b) 210mm
c) 275mm2
d) 198mm

Explanation: A=11t2
= 11×52
= 275mm2

7. In the formula (Mb)max=mω2 $$r\frac{L}{9\sqrt{3}}$$ what is the unit of r?
a) m
b) Km
c) mm
d) Cm

Explanation: In this formula m is the mass of connecting rod, r is the crank radius and L is the length of connecting rod, and r is taken in meters(m).

8. In the formula m=mlL, what is the unit of m?
a) g
b) Ton
c) m
d) Kg

Explanation: Here m is the mass of connecting rod, ml is the mass of connecting rod per unit length and L is the length of connecting rod, and mass is taken in Kg.

9. Calculate the whipping stress when Mb=105.14Kn-mm, y=20mm, and I=143018.66mm4?
a)11.8N/mm2
b)13.79N/mm
c)14.7N/mm2
d)15.9N/mm

Explanation: $$\sigma=\frac{M_bY}{I}$$r
= $$\frac{105.14×10^3×20}{143018.66}$$
= 14.7N/mm2