Vivax Solutions

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Newton's Laws of Motion

  1. The mass of an object is 2 kg and is subjected to a force of 12 N. Find the acceleration of the object. How far will the object move in 4 seconds? Find the velocity gained by the object as well.
  2. The mass of an object is 3 kg and is subjected to two forces of 18 N and 3N that act in opposite directions. Find the acceleration of the object and the distance travelled by it in 4 seconds.
  3. Two forces of 8N and 6N act on an object of 5 kg at right angles. Find the acceleration and the velocity after 4 seconds.
  4. The mass of an object is 2kg and it approaches a rough surface at 20 ms-1 and moves through a distance of 10 m before coming to a halt. Find the time taken for the motion and the force of resistance that acted on the object.
  5. The mass of a motor car is 2000 kg and it moves along a rough road at 20 ms-1 , a constant speed. Find the power of the engine. Then the driving force of the engine is suddenly doubled. Find its initial acceleration.
  6. An object is dropped from a rooftop. Sketch the distance-time graph of the object until it hits the ground and then derive the corresponding velocity-time graph. What are your assumptions?
  7. A balloon is ascending at 20 ms-1 and after three seconds,  an iron ball falls from it. Describe the subsequent motion of the ball and calculate the total distance travelled by the ball, before it hits the ground. How long did the ball take for the motion, since it was dropped?
  8. Three iron blocks are placed on a smooth table so that they are in contact with one another. The masses are 5 kg, 3 kg and 2 kg respectively. A horizontal force of 50 N is applied to the smallest block. Find the reactions between the blocks.
  9. The mass of three wooden blocks are 2 kg, 3 kg and 5 kg respectively. They are placed on the floor of a lift, on top of each other. The lift moves up with an acceleration of 2 ms-2 . Find the reactions between the blocks.
  10. An object is attached to the ceiling of a lift by means of a string. When is it more likely to break? - going up or down. The mass of the object is 5 kg and the lift moves up with an acceleration of 2 ms-2 . Find the tension of the string. Determine the acceleration and the direction of the lift, if the string remains slack.
  11. An object is dropped from a height of 20 m and on impact, it goes through a distance of 5 cm into the soil. Find the resistance offered by sand on the object.
  12. Modern vehicles have  'crumpling zones' fitted at the front. What is the purpose them? How does it protect the passengers against a potential danger?
  13. Parachutists bend their knees, just before landing. Explain its significance.
  14. A hose pipe ejects water at 20 ms-1 .It hits a vertical wall at right angles. Find the force exerted on the wall by the water in the following cases:
    • if the water bounces back
    • if the water comes to rest instantaneously.
    The density of water = 1000 kg/m-3
  15. The wing span of an eagle is said to be 2 m2 . It stays in balance in the air by moving the wings up and down at 20 ms-1 . Find its mass, if the density of air is 0.5 kgm-3 .
  16. A hose pipe vertically ejects water at 20 ms-1 . The power of water can keep a ball in balance, 5 m from the tip of the hose pipe in the air. Find the mass of the ball.
  17. The mass of a railway engine is 2000 kg and and it draws upon two carriages at  a constant speed. The driving force of the engine is 5000 N. Find the tensions of the cables that connect the carriages with each other and the engine. The mass of each carriage is 1000 kg.  If the driving force is doubled, what will be the new tensions of the cables.
  18. The air resistance upon a falling object is said to be directly proportional to its velocity. Sketch a velocity time graph for such an object in these circumstances. Then derive both the distance-time graph and the acceleration-time graph for the same.
  19. A pendulum hangs from a ceiling of a moving car. The mass of the bob is 200 g and the acceleration of the car is 2 ms-2 . Find the inclination of the string against the vertical and its tension. Comment on the positioning of the string.
  20. The mass of an object is 2 kg and is placed on a rough surface with frictional force 2 N. It is being pulled on by a force of 16 N that acts 300 to the horizontal. Find the acceleration of the object and the reaction.
  21. Two objects of different masses are attached to a string, kept it slack and dropped down from the top of a tower. Find the tension of the string while in motion.
  22. When you hit an iron ball, you get hurt. However, it does not happen, when you kick a football. Explain.