9th Class Science Force and laws of motion Question Bank

done Force And Laws Of Motion HOTS Subjective Problems Total Questions - 20

• question_answer1)
  A cricket ball of mass 100 g moving with a speed of 30 m/s is brought to rest by a player. Then find the change in momentum of ball.
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• question_answer2)
  Two bodies have masses in the ratio 3:4. When a force is applied on first body, it moves with an acceleration of\[\text{6 m}/{{\text{s}}^{\text{2}}}\]. How much acceleration will the same force produce in the other body?
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• question_answer3)
  A body of mass 500g is at rest on a frictionless surface. What is the distance travelled by it in 10s when acted upon by a force of\[\text{1}{{0}^{-\text{2}}}\text{ N}\]?
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• question_answer4)
  A body of mass\[30\times {{10}^{-3}}kg\], when acted upon by a force for 5s, attains a velocity of 100 m/s. If the same force is applied for 2 minutes on a body of mass 10 kg at rest, what will be its velocity?
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• question_answer5)
  Weights of two bodies A and B are 500 N and 250 N respectively. If the mass of A is 5 kg, what is the mass of B?
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• question_answer6)
  A sphere of mass 25 kg moving with a velocity of\[\text{4}0\text{ m}{{\text{s}}^{-\text{1}}}\]collides with another sphere of mass 15 kg which is at rest. After collision, if they move with the same velocity, find that velocity?
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• question_answer7)
  A force of 200 dyne acts on a body of mass 10 g for 5 sec. What will be the final velocity of the body if it starts from rest?
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• question_answer8)
  A force of 50 N acts on a body for 10s. What is the change in momentum?
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• question_answer9)
  A body of mass 2 kg moving with uniform velocity of 40 m/s collides with another body at rest. If the two bodies move together with a velocity of 25 m/s. Find the mass of the other body.
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• question_answer10)
  A boy of mass 50 kg running at 5 m/s jumps onto a 20 kg trolley travelling in the same direction at 1.5 m/s. What is their common velocity?
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• question_answer11)
  A 6 kg mass collides with a body at rest. After collision, they travel together with a velocity equal to one-third of the velocity of 6 kg mass. Find the mass of the second body.
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• question_answer12)
  A force of 10 kgwt acting on a certain mass for 2 seconds gave it a velocity of 10 m/s. What is the mass in kg? \[(\text{g}=\text{9}.\text{8m}/{{\text{s}}^{\text{2}}})\]
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• question_answer13)
  A 2000 kg car travelling at 72 km/h runs into a concrete wall and stops in 0.05s. What magnitude of impulse did the wall exert on the car?
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• question_answer14)
  A bullet of mass 'a', velocity 'b' is fired into a large block of wood of mass 'c' which is at rest. After that, both the block of wood and bullet move with a common velocity 'v', then find velocity.
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• question_answer15)
  A car of mass 400 kg travelling at 72 km/h crashes into a truck of mass 4000 kg and travelling at 9 km/ h in same direction. The car bounces back at a speed of 18 km/h. Find the speed of the truck after the impact.
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• question_answer16)
  A pendulum bob of mass 50 g is suspended from the ceiling of an elevator. Find the tension in the string if the elevator (a) goes up with acceleration\[\text{1}.\text{2 m}/{{\text{s}}^{\text{2}}}\], (b) goes up with deceleration 1.2 m/s 2, (c) goes up with uniform velocity, (d) goes down with acceleration\[\text{1}.\text{2 m}/\text{s}{{\text{ }}^{\text{2}}}\], (e) goes down with deceleration \[\text{1}.\text{2 m}/{{\text{s}}^{\text{2}}}\] and (f) goes down with uniform velocity.         
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• question_answer17)
          All the surfaces shown in figure are assumed to be frictionless. The block of mass m slides on the prism which in turn slides backward on the horizontal surface. Draw the free body diagrams of (a) block of mass m (b) prism
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• question_answer18)
  In the arrangement shown in figure. The strings are light and inextensible. The surface over which blocks are placed is smooth. Find: (a) The acceleration of each block (b) The tension in each string.
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• question_answer19)
  Two blocks of mass m = 5 kg and M = 10 kg are connected by a string passing over a pulley B as shown. Another string connects the centre of pulley B to the floor    and    passes    over    another pulley A as shown. An upward force F is applied at the centre of pulley A.   Both the pulleys are massless. Draw the free body diagrams of (a) pulley A (b) pulley B.
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• question_answer20)
  Two blocks A and B of \[{{m}_{A}}\] mass \[{{m}_{B}}\] and Wg respectively are kept in contact on a frictionless table. The experimenter pushes the block A from behind so that the blocks accelerate. If the block A exerts a force F on the block B. What is the force exerted by the experimenter on A?
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