10 objective questions of Force and laws of motion
Answers
Answer:
Exert large force on the ball
(b) Increases the force exerted by the ball on hands
(c) Increase the rate of change of momentum
(d) Decrease the rate of change of momentum
Answer:(d) Decrease the rate of change of momentum
2. An object of mass 2 kg is sliding with a constant velocity of 4 m/s on a friction less horizontal table. The force required to keep the object moving with the same velocity is:
(a) 32 N
(b) 0 N
(c) 2 N
(d) 8 N
Answer:(b) 0 N
3. Newton’s third law of motion explains the two forces namely ‘action’ and ‘reaction’ coming into action when the two bodies are in contact with each other. These two forces:
CBSE Class 9 Science MCQs Chapter 9 Force and Laws of Motion
(a) Always act on the same body
(b) Always act on the different bodies in opposite directions
(c) Have same magnitude and direction
(d) Acts on either body at normal to each other
Answer:(b) Always act on the different bodies in opposite directions
4. In a rocket, a large volume of gases produced by the combustion of fuel is allowed to escape through its tail nozzle in the downward direction with the tremendous speed and makes the rocket to move upward.
CBSE Class 9 Science MCQs Chapter 9 Force and Laws of Motion
Which principle is followed in this take off of the rocket?
(a) Moment of inertia
(b) Conservation of momentum
(c) Newton’s third law of motion
(d) Newton’s law of gravitation
Answer:(b) Conservation of momentum
5. A water tank filled upto 2/3 of its height is moving with a uniform speed. On sudden application of the brake, the water in the tank would
(a) Move backward
(b) Move forward
(c) Come to the rest
(e) Be unaffected
Answer: (b) Move forward
6. Velocity versus time graph of a ball of mass 50 g rolling on a concrete floor is shown in the figure below. What will be the frictional force of the floor on the ball?
CBSE Class 9 Science MCQs Chapter 9 Force and Laws of Motion
(a) 0.5 N
(b) 50 N
(c) 5 N
(d) 0.05 N
Answer:(a) 0.5 N
7. The seat belts are provided in the cars so that if the car stops suddenly due to an emergency braking, the persons sitting on the front seats are not thrown forward violently and saved from getting injured. Can you guess the law due to which a person falls in forward direction on the sudden stopping of the car?
(a) Newton’s first law of motion
(b) Newton’s second law of motion
(c) Newton’s third law of motion
(d) Newton’s law of gravitation
Answer:(a) Newton’s first law of motion
8. When a balloon held between the hands is pressed, its shape changes. This happens because:
(a) Balanced forces act on the balloon
(b) Unbalanced forces act on the balloon
(c) Frictional forces act on the balloon
(d) Gravitational force acts on the balloon
Answer:(a) Balanced forces act on the balloon
9. Which of the following situations involves the Newton’s second law of motion?
(a) A force can stop a lighter vehicle as well as a heavier vehicle which are moving
(b) A force exerted by a lighter vehicle on collision with a heavier vehicle results in both the (vehicles coming to a standstill
(c) A force can accelerate a lighter vehicle more easily than a heavier vehicle which are moving
(d) A force exerted by the escaping air from a balloon in the downward direction makes the balloon to go upwards
Answer:(c) A force can accelerate a lighter vehicle more easily than a heavier vehicle which are moving
10. The speed of a car weighing 1500 kg increases from 36 km/h to 72 km/h uniformly. What will be the change in momentum of the car?
(a) 15000 kg km/h
(b) 15000 kg m/s
(c) 54000 kg m/s
(d) 54000 g m/s
Answer:(b) 15000 kg m/s
Explanation:
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Answer:
1) What is force?
2)What are Newton's three laws of motion?
3) Definition of distance and its unit?
4)difference between distance and Quick.
5)What is inertia and its classification.