০০। A block of mass m1, placed on an inclined smooth plane is connected by a light string passing over a smooth pulley to mass m2, which moves vertically downwards as shown in the below figure. The tension in the string is
ক) m1/m2
খ) m1.g sin α
গ) m1.m2/m1+m2
ঘ)
০১। A block ot mass 20 kg lying on a rough horizontal plane is connected by a light string passing over a smooth pulley to another mass 5 kg, which can move freely in the Vertical direction, as shown in the below figure. The tension in the string will __________ with the increase in coefficient of friction.
ক) increase
খ) decrease
গ) not be effected
০২। A body is said to move or vibrate with simple harmonic motion if its acceleration is directed towards the mean position.
ক) True
খ) False
০৩। A body of mass m moving with a constant velocity v strikes another body of same mass m moving with same velocity but in opposite direction. The common velocity of both the bodies after collision is
ক) v
খ) 2v
গ) 4v
ঘ) 8v
০৪। A body of weight W is required to move up on rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by(where μ = tanφ = Coefficient of friction between the plane and the body.)
ক) P = W tanα
খ) P = W tan(α + φ)
গ) P = W (sinα + μcosα)
ঘ) P = W (cosα + μsinα)
০৫। A body will begin to move down an inclined plane if the angle of inclination of the plane is __________ the angle of friction.
ক) equal to
খ) less than
গ) greater than
০৬। A circular hole of 50 mm diameter is cut out from a circular disc of 100 mm diameter as shown in the below figure. The centre of gravity of the section will lie
ক) in the shaded area
খ) in the hole
গ) at O
০৭। A couple produces
ক) translatory motion
খ) rotational motion
গ) combined translatory and rotational motion
ঘ) none of the above
০৮। A differential pulley block has larger and smaller diameters of 100 mm and 80 mm respectively. Its velocity ratio is
ক) 5
খ) 10
গ) 20
ঘ) 40
০৯। A force acting in the opposite direction to the motion of the body is called force of friction.
ক) Agree
খ) Disagree
১০। A force while acting on a body may
ক) change its motion
খ) balance the forces, already acting on it
গ) give rise to the internal stresses in it
ঘ) all of these
১১। A framed structure is imperfect, if the number of members are __________ (2j - 3).
ক) equal to
খ) less than
গ) greater than
ঘ) either (b) or (c)
১২। A framed structure is perfect, if the number of members are __________ (2j - 3), where j is the number of joints.
ক) equal to
খ) less than
গ) greater than
ঘ) either (b) or (c)
১৩। A framed structure, as shown in the below figure, is a
ক) perfect frame
খ) deficient frame
গ) redundant frame
ঘ) none of the above
১৪। A ladder is resting on a rough ground and leaning against a smooth vertical wall. The force of friction will act
ক) downward at its upper end
খ) upward at its upper end
গ) zero at its upper end
ঘ) perpendicular to the wall at its upper end
১৫। A ladder is resting on a smooth ground and leaning against a rough vertical wall. The force of friction will act
ক) towards the wall at its upper and
খ) away from the wall at its upper end
গ) downward at its upper end
ঘ) upward at its upper end
১৬। A lead ball with a certain velocity is made to strike a wall, it falls down, but rubber ball of same mass and with same velocity strikes the same wall, it rebounds. Select the correct reason from the following:
ক) both the balls undergo an equal change in momentum
খ) the change in momentum suffered by rubber ball is more than the lead ball
গ) the change in momentum suffered by rubber ball is less than the lead ball
ঘ) none of the above
১৭। A lift moves downwards with an acceleration of 9.8 m/s2. The pressure exerted by a man on the floor of the lift is zero.
ক) True
খ) False
১৮। A lifting machine lifts a load of 1000N through a distance of 0.2 m by means of an effort of 200N through a distance of 1m. This machine is an ideal one.
ক) Correct
খ) Incorrect
১৯। A machine having an efficiency greater than 50%, is known as