04%20-%20Laws%20of%20Motion

# 04%20-%20Laws%20of%20Motion - 04 LAWS OF MOTION Page 1...

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04 - LAWS OF MOTION Page 1 ( Answers at the end of all questions ) 1 ) A smooth block is released at rest on a 45 ° incline and then slides a distance ‘d’. The time taken to slide is ‘n’ times as much to slide on rough incline than on a smooth incline. The coefficient of friction is ( a ) µ k = 2 n 1 1 - ( b ) µ k = 2 n 1 1 - ( c ) µ s = 2 n 1 1 - ( d ) µ s = 2 n 1 1 - [ AIEEE 2005 ] 2 ) The upper half of an inclined plane with inclination φ is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom if the coefficient of friction for the lower half is given by ( a ) 2 cos φ ( b ) 2 sin φ ( c ) tan φ ( d ) 2 tan φ [ AIEEE 2005 ] 3 ) A particle of mass 0.3 kg is subjected to a force F = - kx with k = 15 N / m. What will be its initial acceleration if it is released from a point 20 cm away from the origin ? ( a ) 15 m / s 2 ( b ) 3 m / s 2 ( c ) 10 m / s 2 ( d ) 5 m / s 2 [ AIEEE 2005 ] 4 ) Consider a car moving on a straight road with a speed of 100 m / s. The distance at which car can be stopped is [ µ k = 0.5 ] ( a ) 1000 m ( b ) 800 m ( c ) 400 m ( d ) 100 m [ AIEEE 2005 ] 5 ) A machine gun fires a bullet of mass 40 g with a velocity of 1200 ms - 1 . The man holding it can exert a maximum force of 144 N on the gun. How many bullets can he fire per second at the most ? ( a ) one ( b ) four ( c ) two ( d ) three [ AIEEE 2004 ] 6 ) Two masses m 1 = 5 kg and m 2 = 4.8 kg tied to a string are hanging over a light frictionless pulley. What is the acceleration of the masses when lift is free to move ? ( g = 9.8 m / s 2 ) ( a ) 0.2 m / s 2 ( b ) 9.8 m / s 2 ( b ) 5 m / s 2 ( d ) 4.8 m / s 2 [ AIEEE 2004 ] 7 ) A block rests on a rough inclined plane making an angle of 30 ° with the horizontal. The coefficient of static friction between the block and the plane is 0.8. If the frictional force on the block is 10 N, the mass of the block ( in kg ) is ( take g = 10 m / s 2 ) ( a ) 2.0 ( b ) 4.0 ( c ) 1.6 ( d ) 2.5 [ AIEEE 2004 ] 8 ) Three forces start 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 in the figure. The particle will now move with velocity ( a ) less than v ( b ) greater than v ( c ) v remaining unchanged ( d ) l v l in the direction of the largest force BC [ AIEEE 2003 ]

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04 - LAWS OF MOTION Page 2 ( Answers at the end of all questions ) 9 ) A horizontal force of 10 N is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is 0.2. The weight of the block is ( a ) 2 N ( b ) 20 N ( c )
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04%20-%20Laws%20of%20Motion - 04 LAWS OF MOTION Page 1...

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