A force of 50 dynes is acted on a body of mass 5 g which is at rest for an interval of 3 seconds, then impulse is
1. 0.15×10−3 Ns
2. 0.98×10−3 Ns
3. 1.5×10−3 Ns
4. 2.5×10−3 Ns
Three forces starts acting simultaneously on a particle moving with velocity →v. These forces are represented in magnitude and direction by the three sides of a triangle ABC (as shown). The particle will now move with velocity
1. →v remaining unchanged
2. Less than →v
3. Greater than →v
4. →v in the direction of the largest force BC
Two blocks are connected by a string as shown in the diagram. The upper block is hung by another string. A force F applied on the upper string produces an acceleration of 2 m/s2 in the upward direction in both the blocks. If T and T’ be the tensions in the two parts of the string, then
1. T = 70.8 N and T’ = 47.2 N
2. T = 58.8 N and T’ = 47.2 N
3. T = 70.8 N and T’ = 58.8 N
4. T = 70.8 N and T’ = 40.2 N
A block is kept on a frictionless inclined surface with an angle of inclination 'α'. The incline is given an acceleration 'a' to keep the block stationary. Then a is equal to
1. g
2. gtanα
3. g/tanα
4. gcosecα
A block of mass M is pulled along a horizontal frictionless surface by a rope of mass m. If a force P is applied at the free end of the rope, the force exerted by the rope on the block will be:
1. P
2. PmM+m
3. PMM+m
4. PmM−m
Three equal weights A, B and C of mass 2 kg each are hanging on a string passing over a fixed frictionless pulley as shown in the figure The tension in the string connecting weights B and C is
1. Zero
2. 13 N
3. 3.3 N
4. 19.6 N
Two masses of 4 kg and 5 kg are connected by a string passing through a frictionless pulley and are kept on a frictionless table as shown in the figure. The acceleration of 5 kg mass is
1. 49 m/s2
2. 5.44 m/s2
3. 19.5 m/s2
4. 2.72 m/s2
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
1. 7g8; g8
2. 21g8; g8
3. 21g8; g5
4. 12g5; g5
Three blocks A, B and C weighing 1, 8 and 27 kg respectively are connected as shown in the figure with an inextensible string and are moving on a smooth surface. T3 is equal to 36 N. Then T2 is
1. 18 N
2. 9 N
3. 3.375 N
4. 1.25 N
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/s2)
1. 4.9 m/s2
2. 2.45 m/s2
3. 1.4 m/s2
4. 9.5 m/s2