box starts to slip and slides 4 0 m down the plank in 4 0 s The coefficients of static and kinetic friction between the box and the plank will be respectively a 0 5 and 0 6 c 0 6 and 0 6 2015 Three blocks A B and C of masses 4 kg 2 kg and 1 kg respectively are in contact on a frictionless surface as shown If a force of 14 N is applied on the 4 kg block then the contact force between A and B is a 8 N c 2 N c b 0 4 and 0 3 d 0 6 and 0 5 2015 Cancelled 10 A block A of mass m rests on a horizontal table A light string connected to it passes over a frictionless pully at the edge of table and from its other end another block B of mass m is suspended The coefficient of kinetic friction between the block and the table is u When the block A is sliding on the table the tension in the string is a m m 1 8 m m m um 8 m m H A system consists of three masses m m and m3 connected by a string passing over a pulley P The mass m hangs freely and m and m are on a rough horizontal table the b 18 N d 6 N b d m m 1 H 8 m m m m 8 m m 2015 Cancelled P m m M3 a 9 c g 1 2 2014 N The force F acting on a particle of mass m is indicated by the force time graph shown below The change in momentum of the particle over the time interval from zero to 8 s is coefficient of friction The pulley is frictionless and of negligible mass The downward acceleration of mass m is Assume a 24 Ns c 12 Ns b 2gu d g 1 2 2ma g a ma g a 6 r s 2014 13 A balloon with mass m is descending down with an acceleration a where a g How much mass should be removed from it so that it starts moving up with an acceleration a a b 20 N s d 6 Ns b d 2ma g a ma 2014 g a M Three blocks with masses m 2m and 3m are connected by strings as shown in the figure After an upward force F is applied on block m the masses move upward at constant speed w What is the net force on the block of mass 2m g is the acceleration due to gravity a 3mg b 6mg c zero d 2mg m 2m 3m NEET 20 19 An explosion breaks a rock into three parts horizontal plane Two of them go off at r angles to each other The first part of mass moves with a speed of 12 m s and the sec part of mass 2 kg moves with 8 m s spee the third part flies off with 4 m s speed its mass is a 7 kg c 3 kg b 17 kg d 5 kg NEET 16 The upper half of an inclined plan inclination is perfectly smooth while