Class 4 Mechanics

15 Questions | Total Attempts: 41

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Class 4 Mechanics


Questions and Answers
  • 1. 
    If two forces F1 = 120 N and F2=80 N are acting at a point making an angle of 55°between them. Find the resultant of these forces in magnitude.
    • A. 

      179.361 N

    • B. 

      177.361 N

    • C. 

      178.361 N

    • D. 

      175.361 N

  • 2. 
    A body weighing 200 N is resting on a horizontal surface. It is just on the point of moving when a horizontal force of 50 N is applied on it. Find coefficient of friction.
    • A. 

      0.35

    • B. 

      0.25

    • C. 

      0.245

    • D. 

      0.24

  • 3. 
    A body weighing 280 N is at a height 10 m above ground level and moving with a velocity 1.6 m/s. Calculate total energy ( in Joules) possessed by the body.
    • A. 

      2834.53

    • B. 

      2838.53

    • C. 

      2840.53

    • D. 

      2836.53

  • 4. 
    Find power of a pump to fill water tank 3m x 2m x 1.5m in 45 minutes. The water is to be lifted through 12 m height. Assume efficiency of pump= 85%
    • A. 

      463.647 W

    • B. 

      464.647 W

    • C. 

      461.647 W

    • D. 

      465.647 W

  • 5. 
    The power of the machine is 10kW. Find the time taken ( in seconds) to lift a body of mass 1000kg to a height of 20m. 
    • A. 

      20.62

    • B. 

      18.62

    • C. 

      18.11

    • D. 

      19.62

  • 6. 
    A sail boat weighs 8000 N including occupants. The wind exerts a force of 350 N on the boat. The resistance to motion in water is 200 N. Find the acceleration ( in m/s2) of the boat. Take g= 9.81 m/s2
    • A. 

      0.1439

    • B. 

      0.1639

    • C. 

      0.1839

    • D. 

      0.1939

  • 7. 
    A sphere of mass 0.8 kg has a velocity of 1 m/s. It strikes another sphere of mass 0.7 kg which is at rest. The impact is direct central. If the first sphere comes to rest after impact, find velocity ( in m/s)of the second sphere.
    • A. 

      1.043

    • B. 

      1.343

    • C. 

      1.243

    • D. 

      1.143

  • 8. 
    A flywheel starting from rest under uniform acceleration completes one revolution in 8th second. Find angular acceleration after 15 seconds from start.
    • A. 

      0.1333

    • B. 

      0.1423

    • C. 

      0.1123

    • D. 

      0.1313

  • 9. 
    A man weighing 600 N climbs a staircase of 12 m height in 30 seconds. How much power was consumed?
    • A. 

      0.26 kW

    • B. 

      0.20 kW

    • C. 

      0.24 kW

    • D. 

      0.22 kW

  • 10. 
    A pull of 60 N at 25° up the horizontal is required to just move a block of weight(W). Calculate the weight of the block if µ = 0.25
    • A. 

      244.871 N

    • B. 

      240.871 N

    • C. 

      246.871 N

    • D. 

      242.871 N

  • 11. 
    A vehicle is moving with a velocity of 36 km/hr. If weight of the vehicle is 6 kN, find its kinetic energy.
    • A. 

      30581 J

    • B. 

      30591 J

    • C. 

      30571 J

    • D. 

      30751 J

  • 12. 
    A scooter has an initial velocity of 4 m/s. It accelerates for 12 seconds at the rate of 0.25 m/s2. Determine the final velocity after 12 seconds
    • A. 

      7.2m/s

    • B. 

      6.8 m/s

    • C. 

      7.0 m/s

    • D. 

      7.3 m/s

  • 13. 
    A 40 kN block on 24° inclined plane requires a force of 22 kN to move it up the plane. If the applied force is in the direction of plane, find coefficient of friction between the block and plane.
    • A. 

      0.1368

    • B. 

      0.1468

    • C. 

      0.1568

    • D. 

      0.1668

  • 14. 
    A bowler throws a ball with a speed of 20 m/s. The moment the ball touches the ground, it looses its energy by 12 Joule. Calculate the speed (m/s) at which it hits the bat. Neglect air and other resistances. Mass of the ball is 200 gms.
    • A. 

      15.733

    • B. 

      14.733

    • C. 

      16.733

    • D. 

      17.733

  • 15. 
    A sphere of mass 0.8 kg has a velocity of 1 m/s. It strikes another sphere of mass 0.7 kg which is at rest. The impact is direct central. If the first sphere comes to rest after impact, find velocity ( in m/s)of the second sphere.
    • A. 

      1.103

    • B. 

      1.163

    • C. 

      1.123

    • D. 

      1.143