Theory Of Machine - Practice Test

[#276] V-belts are usually used for

(A) Long drives

(B) Short drives

(C) Long and short drives

(D) None of these

Correct Answer

(B) Short drives

[#277] ABCD is a four bar mechanism in which AB = 310 mm and CD = 450 mm. AB and CD are both perpendicular to the fixed link AD, as shown in the below figure. If the velocity of B at this condition is v. Then the velocity of C is

(A) $$frac{1}{3}$$ v

(B) $$frac{2}{3}$$ v

(C) $$frac{3}{2}$$ v

(D) $$frac{9}{4}$$ v

Correct Answer

(C) $$frac{3}{2}$$ v

Explanation

Solution:

[#278] A body is said to be under forced vibrations, when

(A) There is a reduction in amplitude after every cycle of vibration

(B) No external force acts on a body, after giving it an initial displacement

(C) A body vibrates under the influence of external force

(D) None of the above

Correct Answer

(A) There is a reduction in amplitude after every cycle of vibration

[#279] In a vibrating system, if the actual damping coefficient is 40 N/m/s and critical damping coefficient is 420 N/m/s, then logarithmic decrement is equal to

(A) 0.2

(B) 0.4

(C) 0.6

(D) 0.8

Correct Answer

(C) 0.6

[#280] In under damped vibrating system, if $${{x_1}}$$ and $${{x_2}}$$ are the successive values of the amplitude on the same side of the mean position, then the logarithmic decrement is equal to

(A) $$frac{{{x_1}}}{{{x_2}}}$$

(B) $$log frac{{{x_1}}}{{{x_2}}}$$

(C) $$log efrac{{{x_1}}}{{{x_2}}}$$

(D) $$log left( {{x_1} imes {x_2}} ight)$$

Correct Answer

(B) $$log frac{{{x_1}}}{{{x_2}}}$$

Theory Of Machine - Study Mode

[#276] V-belts are usually used for

Correct Answer

[#277] ABCD is a four bar mechanism in which AB = 310 mm and CD = 450 mm. AB and CD are both perpendicular to the fixed link AD, as shown in the below figure. If the velocity of B at this condition is v. Then the velocity of C is

Correct Answer

Explanation

[#278] A body is said to be under forced vibrations, when

Correct Answer

[#279] In a vibrating system, if the actual damping coefficient is 40 N/m/s and critical damping coefficient is 420 N/m/s, then logarithmic decrement is equal to

Correct Answer

[#280] In under damped vibrating system, if $${{x_1}}$$ and $${{x_2}}$$ are the successive values of the amplitude on the same side of the mean position, then the logarithmic decrement is equal to

Correct Answer