PhysicsFlame Institute

4. The mass of a body measured by a physical balance in a lift at rest is found to be m. If the lift is going up with an acceleration a, its mass will be measured as

(a) m (1- a/g) (b) m (1 + a/g) (c) m (d) Zero Ans. c (5)

The relationship between the force F and position x of a body is as shown in figure. The work done in displacing the body from x = 1 m to x = 5 m will be

(a) 30 J (b) 15 J (c) 25 J (d) 20 J Answer: b (4)

The diagrams represent the potential energy U of a function of the inter-atomic distance r. Which diagram corresponds to stable molecules found in nature.

Answer: a (13)

A particle of mass m moving with a velocity u makes an elastic one dimensional collision with a stationary particle of mass m establishing a contact with it for extremely small time T. Their force of contact increases from zero to F0 linearly in time T/4, remains constant for a further T/2 time and decreases linearly from F0 to zero in further time T/4 as shown. The magnitude possessed by F0 is

(a) mu/T (b) 2mu/T (c) 4mu/3T (d) 3mu/4T Answer: c (8)

23. Two masses m1 and m2 (m1 > m2) are connected by massless flexible and inextensible string passed over massless and frictionless pulley. The acceleration of centre of mass is

(a) (m1 – m2 / m1 + m2 ) 2 g (b) m1 – m2 / m1 + m2 g (c) m1 + m2 / m1 – m2 g (d) Zero Ans . a (24)

19. A light string passing over a smooth light pulley connects two blocks of masses m 1 and m 2 (vertically). If the acceleration of the system is g/8 then the ratio of the masses is

(a) 8 : 1 (b) 9 : 7 (c) 4 : 3 (d) 5 : 3 Ans. b (8)

10. A block of mass m1 rests on a horizontal table. A string tied to the block is passed on a frictionless pulley fixed at the end of the table and to the other end of string is hung another block of mass m 2 . The acceleration of the system is on a frictionless pulley fixed at the end of the table and to the other end of string is hung another block of mass . The acceleration of the system is

(a) m 2 g / (m1 + m 2 ) (b) m1 g / (m1 + m 2 ) (c) g (d) m 2 g / m1 Ans. a (47)

11. A 2 kg block is lying on a smooth table which is connected by a body of mass 1 kg by a string which passes through a pulley. The 1 kg mass is hanging vertically. The acceleration of block and tension in the string will be

(a) 3.27 m/s ^ 2 , 6.54 N (b) 4.38,m/s ^ 2 , 6.54 N (c) 3.27 m/s ^ 2 , 9.86 N (d) 4.38,m/s ^ 2 , 9.86 N Ans. a (25)

The force required to stretch a spring varies with the distance as shown in the figure. If the experiment is performed with the above spring of half length, the line OA will

(a) Shift towards F-axis (b) Shift towards X-axis (c) Remain as it is (d) Become double in length Answer: a (12)

Figure shows the F-x Where F is the force applied and x is the distance covered by the body along a straight line path. Given that F is in newton and x in metre, what is the work done ?

(a) 10 J (b) 20 J (c) 30 J (d) 40 J Answer: a (18)

The potential energy of a particle varies with distance x as shown in the graph.

The force acting on the particle is zero at (a) C (b) B (c) B and C (d) A and D Answer: c (28)

The force acting on a body moving along x-axis varies with the position of the particle as shown in the fig.

The body is in stable equilibrium at (a) x=x1 (b) x=x2 (c) both x1 and x2 (d) neither x1 nor x2 Answer: b (11)

Which of the following graphs is correct between kinetic energy (E), potential energy (U) and height (h) from the ground of the particle

Answer: A (8)

If radius of earth is R then the height ‘h’ at which value of ‘g’ becomes one-fourth is

(a) R/4 (b) 3R/4 (c) R (d) R/8 Answer:c (13)

The graph between √E and 1/p is ( E=kinetic energy and p = momentum)

Answer: c (38)

7. Two bodies of mass 3 kg and 4 kg are suspended at the ends of massless string passing over a frictionless pulley. The acceleration of the system is (g = 9.8 m/s ^ 2

(a) 4.9 m/s 2 (b) 2.45 m/s 2 (c) 1.4 m/s 2 (d) …

A particle, initially at rest on a frictionless horizontal surface, is acted upon by a horizontal force which is constant in size and direction. A graph is plotted between the work done (W) on the particle, against the speed of the particle, (v). If there are no other horizontal forces acting on the particle the graph would look like

Answer: d (55)

5. Two masses 2 kg and 3 kg are attached to the end of the string passed over a pulley fixed at the top. The tension and acceleration are

(a) 7g/8 , g/8 (b) 21g/8 , g/8 (c) 21g/8, g/5 (d) 12g/5, g/5 Ans. d (7)

The potential energy of a system is represented in the first figure. the force acting on the system will be represented by

Answer: c (6)

A force F acting on an object varies with distance x as shown here. The force is in newton and x in metre. The work done by the force in moving the object from x=0 to x=6m is

(a) 4.5 J (b) 13.5 J (c) 9.0 J (d) 18.0 J Answer: b (8)

2. A rope of length L is pulled by a constant force F. What is the tension in the rope at a distance x from the end where the force is applied

(a) FL/x (b) F(L-x)/L (c) FL/L-x (d) Fx/L-x Ans. b (5)

The adjoining diagram shows the velocity versus time plot for a particle. The work done by the force on the particle is positive from

(a) A to B (b) B to C (c) C to D (d) D to E Answer: a (8)

A particle is dropped from a height h . A constant horizontal velocity is given to the particle. Taking g to be constant every where, kinetic energy E of the particle w. r. t. time t is correctly shown in

Answer: a (31)

The relation between the displacement X of an object produced by the application of the variable force F is represented by a graph shown in the figure. If the object undergoes a displacement from X=0.5 m to X=2.5 m the work done will be approximately equal to

(a) 16 J (b) 32 J (c) 1.6 J (d) 8 J Answer: a (25)

13. Which of the following groups of forces could be in equibrium

(a) 3 N, 4 N, 5 N (b) 4N, 5 N, 10 N (c) 30N, 40 N, 80 N (d) 1N, 3 N, 5 N Ans. a (8)

A particle of mass 0.1 kg is subjected to a force which varies with distance as shown in fig. If it starts its journey from rest at x=0, its velocity at x=12m is

(a) 0 m/s (b) 20 √2 m/s (c) 20 √3 m/s (d) 40 m/s Answer:d (7)

The graph between the resistive force F acting on a body and the distance covered by the body is shown in the figure. The mass of the body is 25 kg and initial velocity is 2 m/s. When the distance covered by the body is 4m, its kinetic energy would be

(a) 50 J (b) 40 J (c) 20 J (d) 10 J Answer:d (5)

31. For a system to be in equilibrium, the torques acting on it must balance. This is true only if the torques are taken about

(a) The centre of the system (b) The centre of mass of the system (c) Any point on the system (d) Any point on the system or outside it Ans. d (16)

A batsman hits a sixer and the ball touches the ground outside the cricket ground. Which of the following graph describes the variation of the cricket ball’s vertical velocity v with time between the time t1 as it hits the bat and time t2 when it touches the ground

Answer: c (19)

9. Two forces are such that the sum of their magnitudes is 18 N and their resultant is perpendicular to the smaller force and magnitude of resultant is 12 N. Then the magnitudes of the forces are

(a) 12 N, 6 N (b) 13 N, 5N (c) 10 N, 8 N (d) 16 N, 2 N Ans. b (5)

11. Which of the following sets of concurrent forces may be in equilibrium

(a) F1 3N, F2 = 5N, F3 = 9N (b) F1 3N, F2 = 5N, F3 = 9N (c) F1 3N, F2 = 5N, F3 = 9N (d) F1 3N, F2 = 5N, F3 = 6N Ans. d (18)

The relationship between force and position is shown in the figure given (in one dimensional case). The work done by the force in displacing a body from x = 1 cm to x = 5 cm is

(a) 20 ergs (b) 60 ergs (c) 70 ergs (d) 700 ergs Answer: a (9)

7. The resultant of two forces and is R. If the first force is doubled then the resultant is also doubled. The angle between the two forces is

(a) 60 ° (b) 120° (c) 70 ° …

The pointer reading v/s load graph for a spring balance is as given in the figure. The spring constant is

(a) 0.1 kg/cm (b) 5 kg/cm (c) 0.3 kg/cm (d) 1 kg/cm Answer: a (7)

30. A couple produces

(a) Purely linear motion (b) Purely rotational motion (c) Linear and rotational motion (d) No motion Ans. b (7)

8. The resultant of two forces, one double the other in magnitude, is perpendicular to the smaller of the two forces. The angle between the two forces is

(a) 60° (b) 120° (c) 150 ° (d) …

6. The resultant force of 5 N and 10 N can not be

(a) 12 N (b) 8 N (c) 4 N (d) 5 N Ans. c (12)

5. An object is subjected to a force in the north-east direction. To balance this force, a second force should be applied in the direction

(a) North-East (b) South (c) South-West (d) West Ans. c (35)

4. A force-time graph for a linear motion is shown in figure where the segments are circular. The linear momentum gained between zero and 8 second is

(a) -2π newton×second (b) Zero newton×second (c) +4π newton×second (d) -6π newton×second Answer: b (10)

26. When a ceiling fan is switched on, it makes 10 rotations in the first 3 seconds. How many rotations will it make in the next 3 seconds (Assume uniform angular acceleration)

(a) 10 (b) 20 (c) 30 (d) 40 Ans. c (11)

Physics

Login with your site account

Register a new account