Eamcet - Physics - Newtons Laws Of Motion Including Friction

A bucket filled with water is tied to a rope of length 0.5 m and is rotated in a circular path in vertical plane. The least velocity it should have at the lowest point of circle so that water doesnot spill is, (g = 10 ms-2 )

A.  √5 m/s

B.  √10 m/s

C.  5 m/s

D.  2√5 m/s

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An eraser weighing 2N is pressed against the black board with a force of 5N. If the co-efficient of friction is 0.4. How much force parllel to the black board is required to slide the eraser upwards

A.  2N

B.  2.8N

C.  4N

D.  4.8N

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If a body is in equilibrium under a set of non-collinear forces, the minimum number of forces has to be

A.  four

B.  three

C.  two

D.  five

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The rear side of truck is open and box of mass 50kg is placed at 3.2m away from the open end.The coefficient of friction between the box and the surface is 0.2. if the truck starts from rest and moves on a straight road with acceleration 2.1ms-2 the box falls off the truck after a time (g=10ms-2)

A.  (8/√41)s

B.  4s

C.  8s

D.  √8s

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A motor car of mass 300 kg is moving with a velocity of 25 m/s, by applying brakes the car was brought to rest in a distance of 15 metres. The force of retardation in newton is :

A.  2500

B.  4500

C.  6250

D.  7500

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The weight of a man in a lift moving upwards is 608 N while the weight of the same man in the lift moving downwards, with the same acceleration is 368 N. His normal weight in N is:

A.  498

B.  588

C.  480

D.  240

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A block of mass 10kg lying on a smooth horizontal surface is being pulled by means of a rope of mass 2kg.If a force of 36N is applied at the end of the rope. The tension at the midpoint of the rope is

A.  33N

B.  30N

C.  24N

D.  12N

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A body of weight "64N" is pushed with just enough force to start it moving across a horizontal floor and the same force continues to act afterwards, if the coefficients of static and dynamic friction are 0.6 and 0.4 respectively, the acceleration of the body is: (acceleration due to gravity = g)

A.  g/6.4

B.  0.64g

C.  g/32

D.  0.2g

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A person aiming to reach the exactly opposite point on the bank of a stream is swimming with a speed of 0.5ms-1 at an angle of 1200 with the direction of flow of water.The speed of water in the stream, in ms-1, is:

A.  1.00

B.  1/√3

C.  0.25

D.  0.433

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A body is sliding down on a rough inclined plane of inclination 45. The time taken by it to slide down on the rough inclined plane is 3 times the time taken by the body to slide down the smooth inclined plane of same inclination and length. The co-efficient of friction between the rough inclined plane and the body is

A.  1/3

B.  2/3

C.  1/9

D.  8/9

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The maximum tension a rope can withstand is 60 kg wt The ratio of maximum acceleration with which two boys of masses 20 kg and 30 kg can climb up the rope at the same time is

A.  1:2

B.  2:1

C.  4:3

D.  3:2

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A body 'A' starts from rest with an acceleration 'a1'. After 2 seconds another body 'B' starts from rest with an acceleration a2.If they travel equal distance in the 5th second after the start of 'A'.a1:a2 equal to:

A.  5:9

B.  5 : 7

C.  9 : 5

D.  9 : 7

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