1 Two forces (8iˆ+10jˆ)N and (4iˆ+8jˆ)N are acting on a body of mass 6kg then acceleration produced in the body in m/s2 will be
-(1) (3iˆ+2jˆ) (2) 12iˆ+18jˆ
(3) (iˆ jˆ) 3
1 + (4) 2iˆ+3jˆ
2 A block of mass M placed on a smooth horizontal surface is pulled by a constant force F acting at an angle θ with the horizontal. The acceleration produced in the block is a. Then
-(1) If a ≤ g/tanθ, the acceleration is along the horizontal direction θ F
M (2) If a ≤ g/tanθ, the normal reaction is N = M (g – a tanθ)
(3) The acceleration a will not be parallel to the applied force F.
(4) all of the above
3 Two objects A and B each of mass m are connected by a light inextensible string.
They are restricted to move on a frictionless ring of radius R in a vertical plane (as shown in fig). The objects are released from rest at the position shown. Then, the tension in the cord just after release is
-(1) zero (2) mg
T T B 45º
A
(3) 2 mg (4) mg/ 2
4 In the arrangement shown in figure m1 = 8kg, m2 = 2kg and spring constant K = 1600 N/m. All surfaces are smooth then
-(1) Tension in string, T = 17.2N
m1
m2 (2) Tension in string, T = 15.68 N
(3) Extension in spring is 9.8 mm (4) Extension in spring is 12 mm
5 A metallic sphere is suspended on stationary wall with the help of a spring. Forces as shown in the fig. are acting on the sphere. Which statement/statements in following is true
-(a) N + T + W = 0 (b) T2 = N2 + W2
T N
(c) T = N + W (d) N = W tanθ W
(1) a, b, c (2) b, c, d
(3) a, b, d (4) a, b, c, d
6 A chain has five rings. The mass of each ring is 0.1 kg. This chain is pulled upwards by a force F producing an acceleration of 2.50 m/s2 in the chain. Then the force of action (reaction) on the joint of second and third ring from the top is
-(1) 0.25 N (2) 1.23 N
1 2
3 4
5 F
(3) 3.69 N (4) 6.15 N
7 A machine-gun of mass M fires n bullets per second. The mass of each bullet is m and speed is v. Force acting on the machinegum is
-(1) v
8 Force are acting on a body according to fig. If body is moving horizontally at a constant speed of 5 m/s then value of P and S respectively will be
-(1) 0N, 0N (2) 300 N, 200 N
9 A & B are two particles of mass m each, are kept stationary as shown in fig. by applying a horizontal force F = mg on B then
10 In fig. speed of each particle after 4 sec.
-(1) 0.872 m/s (2) 8.72 m/s
11 Linear momentum of P of a body performing one dimensional motion is changing according to P = at3 + bt where a and b are positive constants then net force acting on the body is proportional to
-(1) t2 (2) a constant
(3) t (4) 1/t
12 Two monkey A & B are of masses M and m respectively (M > m). They are holding a rope which is passing through a stationary smooth pulley.They moves on rope such that upward acceleration of B becomes double of downward acceleration of A then tension in the rope will be
-(1) 2M m
13 Block B is moving towards right with constant velocity v0. Velocity of block A with respect to block B is (Assume all pulleys and strings are ideal)
(1) v0/2 left (2) v0/2 right A B v0
(3) 3/2v0 right (4) 3/2v0 left
14 If masses are released from the position shown in fig. then speed of mass m1 just before to collide on floor will be
(1) [2m1gd/(m1+m2)]1/2 (2) [2(m1–m2)gd/(m1+m2)]1/2 m2
m >m1 2 (3) [2(m1–m2)gd/m1]1/2 (4) none of these d
15 A frictionless pulley of negligible weight is suspended from a spring balance as shown in fig. Masses of 1kg and 5 kg are tied to the ends of string which passes over the pulley. The masses move due to gravity. The reading of the balance will be
(1) more than 6 kg (2) 6 kg
5kg 1kg
(3) less than 3 kg
(4) less than 6kg and more than 3kg
16 Two bodies A and B are thrown upwards simultaneously with same speed. Mass of A is more than that of B. If same constant resistive force is applied on both bodies by air then
-(1) Both bodies will reach up to same height (2) A will reach up to more height than B (3) B will reach upto more height than A
(4) Any one of above three may be possible, it depends on initial speed of both bodies 17 In the arrangement shown in fig. friction between block & table is
negligible. If F is pulling force and m1 & m2 are known masses then tension in string will be
-(1) m1F/(m1 + m2) (2) 2m1F/(m1 + m2) m1
F m2
(3) 2m1F/(4m1 + m2) (4) none of these
18 A person is standing on a floor of lift, releases a coin. Coin reaches on floor in time t1 if lift is stationary.
and coin reaches on floor in time t2 if lift is moving with uniform velocity -(1) t1 = t2
(2) t1 < t2 (3) t1 > t2
(4) t1 < t2 or t1 > t2 depends on lift on moving downwards or upwards
19 A smooth wedge is kept in a chamber. Chamber is suspended close to earth surface. A block B is kept on top of wedge. It takes time T to slip over length of wedge. If block is kept on top of wedge
& suddenly string breaks then at this time block
-(1) will take more time than T to slip over wedge (2) will take less than T to slip over wedge (3) will remain on top of wedge (4) will fall away from wedge
20 A particle is seen from reference frame s1 & s2. Reference frame s2 is moving with acceleration a with respect to reference frame s1. Assuming F1 & F2 are pseudo force on particle, while we see from frames s1 & s2 respectively. Which of following is not possible
-(1) F1 = 0, F2 ≠ 0 (2) F1 ≠ 0, F2 ≠ 0
22 If downward acceleration is given to the system in the figure of the privisous questino then ratio in string T1 : T2 is
(4) none of these
23 When same force is applied on n different bodies then accelerations produced in them are respectively 1, 1 1 1, , ,...1
2 3 4 n (all in m/s2). If all these bodies are joined together & same force is applied then acceleration will be
-(1) 2
24 On a rod of length L & mass m how much tension will be at a distance y from F1 when two dissimilar forces F1 & F2 (F2 < F1) are applied on the rod
25 A 50 kg mass is on an inclined plane at one end of a massless string passing through a smooth pulley of inclined plane and at other end of the string a 40 kg mass is suspended as shown in fig. distance travelled by 50 kg mass in 4 sec. will be (angle of inclination of plane is 30º)