Inertia Forces in Reciprocating Parts topics include: Kliens, bennetts and ritterhaus construction, velocity and acceleration of engines, reciprocating parts of engines. Inertia forces in reciprocating parts are caused by the oscillation of reciprocating masses. These forces act along the line of stroke and through the cross head on the structures and on the main bearing of the crankshaft.  The inertia force due to the acceleration of the reciprocating parts opposes the force on the piston. The inertia force due to retardation of the reciprocating parts helps the force on the piston.  The... Show more

Inertia Forces in Reciprocating Parts topics include: Kliens, bennetts and ritterhaus construction, velocity and acceleration of engines, reciprocating parts of engines.

Inertia forces in reciprocating parts are caused by the oscillation of reciprocating masses. These forces act along the line of stroke and through the cross head on the structures and on the main bearing of the crankshaft. 

The inertia force due to the acceleration of the reciprocating parts opposes the force on the piston. The inertia force due to retardation of the reciprocating parts helps the force on the piston. 
The inertial force of mass can be calculated by multiplying the object's mass by its acceleration. 
Balancing is a method of correcting or eliminating unwanted inertia forces and couples in rotating and reciprocating parts of the machine.

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Machine Dynamics Practice Test: Inertia Forces in Reciprocating Parts

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25 Questions

1. From the data given:
crank-pin circle radius = 300mm
mass of the reciprocating parts = 250kg
difference between the driving and the back pressures is 0.45 N/mm²
The connecting rod length between centres is 1.2 m and the cylinder bore is 0.5 m.
engine runs at 250 r.p.m & 30° from T.D.C.
Find the piston effort.

37.3 kN40.2 N35.2 kN32.4 kN

2. In a horizontal engine, reciprocating parts are retarded when the piston moves from _________

BDC to TDCBDC to midwayMidway to TDCTDC to BDC

3. In a slider crank mechanism, the length of the crank and connecting rod are 150 mm and 600 mm respectively. The crank position is 60° from inner dead centre. The crank shaft speed is 400 r.p.m. (clockwise). Velocity of the slider is ________

6.66 m/s7.32 m/s6.12 m/s6.9 m/s

4. A body remains in equilibrium if ________

Inertia force is applied in the same direction to the resultant forceInertia force is applied in the direction Perpendicular to the resultant forceInertia force is applied in the direction Parallel to the resultant forceInertia force is applied in the direction opposite to the resultant force

5. In a horizontal engine, the weight of the reciprocating parts also add/subtract to the piston effort.

Don't KnowFalseMaybeTrue

6. Considering a four bar chain with each link having linear and angular acceleration, applying D-Alembert’s principle will never result in which of the following member?

2- force member4 – force member3- force memberNon accelerating member

7. If OC is the crank and PC is the connecting rod rotating in clockwise direction in the figure given below, then triangle OCM is known as _________

Bennett’ acceleration diagramKlein’s acceleration diagramBennett’ velocity diagramKlein’s velocity diagram

8. In given figure, Triangle OCM is known as ________

Klein’s acceleration diagramKlein’s displacement diagramKlein’s velocity diagramBennet’s diagram

9. In a slider crank mechanism, the length of the crank and connecting rod are 180 mm and 540 mm respectively. The crank position is 45° from inner dead centre. The crank shaft speed is 450 r.p.m. (clockwise), calculate angular velocity of the connecting rod in rad/s.

11.112.211.810.3

10. If OC is the crank and PC is the connecting rod of a reciprocating steam engine and rotates with uniform angular velocity in clockwise direction in the given figure below: then under which condition the piston will undergo retardation?

N lies to the right of ON is below ON lies to the left of ON is above O

11. From figure, acceleration of P with respect to C is given by_________

ω2.PCω2.OMω2.CNω2.QN

12. When the acceleration of the piston is 0, then the velocity is _____

MaximumHalf the maximumMinimumNegative

13. The net force acting on the crosshead pin is known as __________

Crank pin effortPiston effortShaft effortCrank effort

14. For a slider crank mechanism, the total no. of dead centres are _____

0123

15. With respect to the figure given quadrilateral CQNO is known as _______

Bennet’s diagramKlein’s velocity diagramKlein’s acceleration diagramKlein’s displacement diagram

16. Why the inertia torque acts in the opposite direction to the accelerating couple?

Bring the body in equilibriumTo reduce the accelerating torqueActs as a constraint torqueIncrease the linear acceleration

17. A Piston will remain in equilibrium if ________

Inertia force is applied in the direction opposite to the resultant forceInertia force is applied in the direction Parallel to the resultant forceInertia force is applied in the direction Perpendicular to the resultant forceInertia force is applied in the same direction to the resultant force

18. From the data given:
The length of the crank and connecting rod are 150 mm and 600 mm
The crank position is 60° from inner dead centre. The crank shaft speed is 400 r.p.m.
Find the acceleration in m/s² of the slider.

101.597.698.6100.6

19. Which of the following expression represent the angular acceleration α of the connecting rod?

ω2 . sin θ.n−ω2 . cos θ.nω2. cos θ/n−ω2 . sin θ/n

20. Inertia torque acts in the same direction as the accelerating couple?

MaybeFalseDon't KnowTrue

21. Ritterhaus’ construction is used when the motion of the crank is linear shm.

TrueMaybeDon't KnowFalse

22. From the data given:
Crank and connecting rod of a steam engine are 0.3 m and 1.5 m in length; The crank rotates at 150 r.p.m. clockwise.
Determine the acceleration in m/s² of the piston for the same position(angle 40 degrees from IDC).

55.2559.2765.350.41

23. D-Alembert’s principle is used for which of the following?

To calculate angular momentum of a system of massesTo calculate moment of inertia of rigid bodiesChange dynamic problem to static problemChange static problem into a dynamic problem

24. Which of the following construction methods is not used to calculate the velocity and acceleration of reciprocating parts of the internal combustion engine?

D-Alembert’s constructionsBennett’s constructionKlien’s constructionRitterhaus’s construction

25. In the following picture the G is the center of gravity, the quantity h is known as the “offset”. I is the moment of inertia and k is the radius of gyration. Offset’s value is given by?

I/m.km.k/II.α/FI.α/m.g