Engineering Mechanics

(^552) „„„„„ A Textbook of Engineering Mechanics

8. Define the term ‘length of equivalent simple pendulum’. Obtain an expression for the
   same.


9. What is a conical pendulum? How does it differ from a simple pendulum?

OBJECTIVE TYPE QUESTIONS

1. One end of a helical spring is fixed while the other carries a load W. The weight moves
   with simple harmonic motion, whose frequency of motion is

(a) 2 π g

δ

(b) 2

g

δ

π (c)^1

2

g

πδ

(d)^1

2 g

δ

π

2. The periodic time of one oscillation for a simple pendulum is

(a)

1

2

l

π g

(b)

1

2

g

π l

(c) 2

l

g

π (d)^2

g

l

π

3. In order to double the period of simple pendulum, the length of the string should be
   (a) halved (b) double (c) quadrupled


4. Which of the following statement is wrong?
   (a) If two springs of stiffness s 1 and s 2 are arranged in series, then stiffness of the equiva
   lent spring is s 1 + s 2.
   (b) The motion of a body from one extremity to another is known as beat.
   (c) A pendulum, which executes one beat per second is known as second’s pendulum.
   (d) none of them.


5. If a simple pendulum is taken 1 km below the earth’s surface in a mine, it will lose in time.
   (a) Yes (b) No


6. The centre of percussion is below the centre of gravity of the body is at a distance equal to

(a) G 2

k

h

(b)

2

kG

h

(c)

G

h

k

(d)

2

G

h

k

7. The periodic time of a conical pendulum is

(a) 2

h

g

π (b) 2

g

h

π (c)

1

2

h

π g

(d)

1

2

g

π h

ANSWERS

1. (c) 2. (c) 3. (c) 4. (a) 5. (b) 6. (b) 7. (a)

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