The unbalanced force due to reciprocating masses

The primary unbalanced force due to inertia of reciprocating parts in a reciprocating engine is given by (where m = Mass of reciprocating parts, $$\omega $$ = Angular speed of crank, r = Radius of crank, $$\theta $$ = Angle of inclination of crank with the line of stroke and n = Ratio of the length of connecting rod to radius of crank)

A

$${\text{m}}{\omega ^2}{\text{r}}\sin \theta $$

B

$${\text{m}}{\omega ^2}{\text{r}}\cos \theta $$

C

$${\text{m}}{\omega ^2}{\text{r}}\frac{{\sin 2\theta }}{{\text{n}}}$$

D

$${\text{m}}{\omega ^2}{\text{r}}\frac{{\cos2\theta }}{{\text{n}}}$$

The secondary unbalanced force due to inertia of reciprocating parts in a reciprocating engine is given by (where m = Mass of reciprocating parts, $$\omega $$ = Angular speed of crank, r = Radius of crank, $$\theta $$ = Angle of inclination of crank with the line of stroke and n = Ratio of the length of connecting rod to radius of crank)

A

$${\text{m}}{\omega ^2}{\text{r}}\sin \theta $$

B

$${\text{m}}{\omega ^2}{\text{r}}\cos \theta $$

C

$${\text{m}}{\omega ^2}{\text{r}}\frac{{\sin 2\theta }}{{\text{n}}}$$

D

$${\text{m}}{\omega ^2}{\text{r}}\frac{{\cos2\theta }}{{\text{n}}}$$

The secondary unbalanced force is __________ the primary unbalanced force.

A

One-half

B

Two-third

C

n times

D

$$\frac{1}{{\text{n}}}$$ times

The unbalanced force due to revolving masses

A

Varies in magnitude but constant in direction

B

Varies in direction but constant in magnitude

C

Varies in magnitude and direction both

D

Constant in magnitude and direction both

In a reciprocating engine, usually __________ of the reciprocating masses are balanced.

A

One-half

B

Two-third

C

Three-fourth

D

Whole

The unbalanced primary forces in a reciprocating engine are

A

Balanced completely

B

Balanced partially

C

Balanced by secondary forces

D

Not balanced

The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, $$\omega $$ = Angular speed of crank, r = Radius of crank and $$\theta $$ = Angle of inclination of crank to the line of stroke)

A

$${\text{m}}{\omega ^2}{\text{r}}\cos \theta $$

B

$${\text{cm}}{\omega ^2}{\text{r}}\sin \theta $$

C

$$\left( {1 - {\text{c}}} \right){\text{m}}{\omega ^2}{\text{r}}\left( {\cos \theta - \sin \theta } \right)$$

D

$${\text{m}}{\omega ^2}{\text{r}}\left( {\cos \theta - \sin \theta } \right)$$

The rainfall due to upward movement of air caused by convergence of cold air masses against warm air masses is called ________.

A

Cyclonic rainfall

B

Orographic rainfall

C

Frontal rainfall

D

Convectional rainfall

In a locomotive, the resultant unbalanced force due to the two cylinders along the line of stroke, is known as

A

Tractive force

B

Swaying couple

C

Hammer blow

D

None of these

By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. The saving in case of a double acting reciprocating pump is

A

39.2%

B

48.8%

C

84.8%

D

88.4%

The unbalanced force due to reciprocating masses

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