Laws of Motion

A wooden block of mass 5 kg rests on a soft horizontal floor. When an iron cylinder of mass 25 kg is placed on the top of the block, the floor yields and the block and the cylinder together go down with an acceleration of 0.1 ms-2. The action force of the system on the floor is equal to :

1. 297 N
2. 291 N
3. 196 N
4. 294 N

Three blocks M1, M2, M3 having masses 4 kg, 6 kg and 10 kg respectively are hanging from a smooth pulley using rope 1, 2 and 3 as shown in figure. The tension in the rope 1, T1 when they are moving upward with acceleration of 2 ms-2 is N (if g = 10 m/s2). [figure]

A particle moves in x-y plane under the influence of a force F such that its linear momentum is p(t) = i (kt) - j (kt). If k is constant, the angle between F and p will be :

1. 2
2. 3
3. 4
4. 6

A heavy box of mass 50 kg is moving on a horizontal surface. If co-efficient of kinetic friction between the box and horizontal surface is 0.3 then force of kinetic friction is :

1. 1470 N
2. 147 N
3. 1.47 N
4. 14.7 N

A wooden block, initially at rest on the ground, is pushed by a force which increases linearly with time t. Which of the following curve best describes acceleration of the block with time :

1. [figure]
2. [figure]
3. [figure]
4. [figure]

A 2 kg brick begins to slide over a surface which is inclined at an angle of 45 with respect to horizontal axis. The co-efficient of static friction between their surfaces is:

1. 1
2. 1.7
3. 0.5
4. 1 3

Consider a block and trolley system as shown in figure. If the coefficient of kinetic friction between the trolley and the surface is 0.04, the acceleration of the system in ms-2 is : (Consider that the string is massless and unstretchable and the pulley is also massless and frictionless) : [figure]

1. 1.2
2. 4
3. 3
4. 2

A ball of mass 0.5 kg is attached to a string of length 50 cm. The ball is rotated on a horizontal circular path about its vertical axis. The maximum tension that the string can bear is 400 N. The maximum possible value of angular velocity of the ball in rad/s is :

1. 1600
2. 20
3. 40
4. 1000

A body of mass 4 kg experiences two forces F1=5 i+8 j+7 k and F2=3 i-4 j-3 k. The acceleration acting on the body is :

1. 2 i+ j+ k
2. 4 i+2 j+2 k
3. -2 i- j- k
4. 2 i+3 j+3 k

A cricket player catches a ball of mass 120 g moving with 25 m/s speed. If the catching process is completed in 0.1 s then the magnitude of force exerted by the ball on the hand of player will be (in SI unit) :

1. 30
2. 24
3. 12
4. 25