Questions and answers for exam Preparation

MCQs

Total Questions : 1284 | Page 126 of 129 pages

Question 1251. A shell of mass 100 kg travelling with a velocity of 10 m/sec breaks into two equal pieces during an explosion which provides an extra kinetic energy of 20000 Joules. If the pieces continue to move in the same direction as before, then the speed of the faster one must be

20 m/sec
40 m/sec
30 m/sec
50 m/sec

Discuss Question

Answer: Option C. -> 30 m/sec

Question 1252. One end of an elastic string of natural length ‘l’ and modulus ‘X’ is kept fixed while to the other end is attached a particle of mass m which is hanging freely under gravity. The particle is pulled down vertically through a distance ‘x’, held at rest and then released.The motion is

A rectilinear motion with constant speed
A simple harmonic motion
None of these
A damped oscillatory motion

Discuss Question

Answer: Option B. -> A simple harmonic motion

Question 1253. The beam shown in below figure is supported by a hinge at ‘A’ and a roller at ‘B’. The reaction RA of the hinged support ‘A’ of the beam, is

10.6 t
10.2 t
10.4 t
10.8 t

Discuss Question

Answer: Option B. -> 10.2 t

Question 1254. A 2 m long ladder rests against a wall and makes an angle of 30° with the horizontal floor. Where will be the instantaneous center of rotation when the ladder starts slipping ?i. 1.0 in from the wallii. 1.732 m from the walliii. 1.0 m above the flooriv. 1.732 m above the floorThe correct answer is

(i) and (iii)
(i) and (iv)
(ii) and (iv)
(ii) and (iii)

Discuss Question

Answer: Option C. -> (ii) and (iv)

Question 1255. If a body is lying on a plane whose inclination with the horizontal is less than the angle of friction, theni. a force is required to move the body upwardsii. a force is required to move the body downwardiii. the body will not be in equilibriumThe correct answer is

both (i) and (ii)
only (i)
only (ii)
both (i) and (iii)

Discuss Question

Answer: Option A. -> both (i) and (ii)

Question 1256. One end of an elastic string of natural length / and modulus X is kept fixed while to the other end is attached a particle of mass m which is hanging freely under gravity. The particle is pulled down vertically through a distance x, held at rest and then released. The motion is

a rectilinear motion with constant speed
a simple harmonic motion
a damped oscillatory motion
None of these

Discuss Question

Answer: Option B. -> a simple harmonic motion

Question 1257. The torque produced by a force depends oni. the magnitude of the forceii. the direction of the forceiii. the point of application of the force relative to originThe correct answer is

all (i), (ii) and (iii)
both (i) and (ii)
both (i) and (iii)
only (i)

Discuss Question

Answer: Option A. -> all (i), (ii) and (iii)

Question 1258. A body A of mass 6.6 kg which is lying on a horizontal platform 4.5 m from its edge is connected to the end of a light string whose other end is supporting a body of mass 3.2 kg as shown in below figure. If the friction between the platform and the body A is 1/3, the acceleration is

0.5 m/sec²
0.75 m/sec²
1.00 m/sec²
1.25 m/sec²

Discuss Question

Answer: Option C. -> 1.00 m/sec²

Question 1259. A stone was thrown vertically upwards from the ground with a velocity of 50 m/sec. After 5 seconds another stone was thrown vertically upwards from the same place. If both the stones strike the ground at the same time, then the velocity with which the second stone was thrown should be (Assume g = 10 m/sec²)

50 m/sec
40 m/sec
25 m/sec
15 m/sec

Discuss Question

Answer: Option C. -> 25 m/sec

Question 1260. A ladder of weight 'w' rests against a smooth vertical wall, and rests on rough horizontal ground, the coefficient of friction between the ladder and the ground being 1/4. The maximum angle of inclination of the ladder to the vertical, if a man of weight 'w' is to walk to the top of it safely, is tan'1 x, where x is

Discuss Question

Answer: Option A. -> 1/3