MCQ
321. A single force and a couple acting in the same plane upon a rigid body-
balance each other
cannot balance each other
produce moment of a couple
are equivalent
322. The ratio of limiting friction and normal reaction is known as-
coefficient of friction
angle of friction
angle of repose
sliding friction
323. The resultant of two force P & Q Such that P >Q) acting along the same straight line but in opposite direction is given by-
P+Q
P-Q
P/Q
Q/P
324. The resultant of two forces P and Q acting at an angle is
√P ² + Q ² + 2PQ sinθ
√P ² + Q ² + 2PQcosθ
√P ² + Q ² -2PQ sinθ
√P ² + Q ²- 2PQcosθ
325. The angle of inclination of the plane at which the body beings to move down the plane is called-
angle of friction
angle of repose
angle of projection
gone of those
326. Two non-collinear parallel equal forces acting in opposite direction-
balance each other
constitute a moment
constitute a couple
constitute a moment of couple
327. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if-
the floor is smooth, the wall is rough
the floor is rough, the wall is smooth
the floor and wall both are smooth surfaces
the floor and wall both are rough surfaces
328. A weight 'W' kg rest on a spring of spring constant K= 8kg/cm. The deflection of the spring due to weight is 4cm. The weight 'W' is-
16kg
32kg
64kg
128kg
329. If three forces acting in different planes can be represented by a triangle, these will be in-
non-equilibrium
partial equilibrium
full equilibrium
unpredictable
330. The friction experienced by a body, when at rest, is known as-
station friction
dynamic friction
limiting friction
coefficient of friction
331. Least force required to draw a body up the inclined. plane is W sin (plane inclination + friction angle) applied in the direction-
along the plane
horizontally
vertically
at an angle equal to the angle of friction to the inclined plane
332. Angle of friction is the-
angle between normal reaction and the resultant of normal reaction and the limiting friction
ratio of limiting friction and normal reaction
the ratio of minimum friction force to the friction force acting when the body is just about to move
the ratio of minimum friction force to friction force acting when the body is in motion
333. The resultant of the following three couples 20 kg force, 0.5 m arm, + ve sense 30 kg force, 1 m arm - ve sense 40 kg force, 0.25 m arm, + ve sense having arm of 0.5 m will be-
20 kg. (-ve) sense
20 kg. (+ve) serse
10 kg. (+ve) sense
10 kg. (-ve) sense
334. A block sliding down an inclined plane has acceleration - acceleration due to gravity.
less than
greater than
same as
none of the above
335. According to Lami's theorem-
three forces acting at a point will be in equilibrium
three forces acting at a point can be represented by a triangle, each side being proportional to force
if three forces acting upon a particle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium
if three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two
336. The unit of force in SI system of units is-
Dyne
Kilogram
Newtch
Watt
337. The coefficient of friction depends on
area of contact
shape of surfaces
strength of surfaces
nature of surface
338. The ratio of static friction to dynamic friction Is always-
equal to one
stream line
steady
turbulent
None
339. Which one of the following statements is not correct-
the tangent of the angle of friction is equal to coefficient of friction
the angle of repose is equal to angle of friction
the tangent of the angle of repose is equal to coefficient of friction
the sine of the angle of repose is equal to coefficient to friction
340. The friction experience by a body, when at rest is known as-
static friction
dynamic friction
limiting friction
coefficient of friction