can anyone give me imp MCQs of force and law of motion
Answers
Answer:
a) 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
Explanation:
Multiple Choice Questions
Question 1.
Rocket works on the principle of conservation of:
(a) mass
(b) energy
(c) momentum
(d) velocity
Question 2.
Among the equal-sized stone and a football, the inertia will be higher of:
(a) football
(b) stone
(c) both
(d) none of them
Question 3.
A batsman hits a cricket ball which then rolls on the ground. After covering a short distance, the ball comes to rest. The ball slows to a stop because:
(a) the batsman did not hit the ball hard enough.
(b) velocity is proportional to the force exerted on the ball.
(c) there is a force on the ball opposing the motion.
(d) there is no unbalanced force on the ball so the ball would want to come to rest.
Question 4.
What is the momentum of an object of mass m, moving with a velocity v?
(a) (mv)2
(b) mv2
(c) 12 mv2
(d) mv
Question 5.
Friction is:
(a) useful to us
(b) harmful to us
(c) both useful as well as harmful to us
(d) none of them.
Fill in the Blanks.
Question 6.
The SI unit of momentum is _________.
Question 7.
The natural tendency of objects to resist a change in their state of rest or of uniform motion is called ______
Question 8.
To every action, there is an ______ and opposite reaction.
Question 9.
The resultant force of balanced forces is ________
Question 10.
The force can change the motion, direction, or _______ of an object.
Question 11.
The value of inertia depends on the _______ of an object.
Question 12.
The rate of change of momentum of an object is ______ to the applied unbalanced force in the direction of the force.
True/False.
Question 13.
In 1586, Galileo Galilei wrote his first scientific book ‘The Little Balance’.
Question 14.
In practical situations, it is difficult to achieve a zero balanced force.
Question 15.
Force is a scalar quantity.
Question 16.
The mass of an object is a measure of its inertia.
Question 17.
In an isolated system, the total momentum remains conserved.
Match the Column.
Question 18.
A B
1. Unit of force (i) Mass × acceleration
2. Unit of pressure (ii) kgms-1
3. Test of purity of milk (iii) Pascal
4. Force (iv) Lactometer
5. S.I unit of momentum (v) Newton
Answer in one Word/Sentence.
Question 19.
Write the unit of pressure.
Question 20.
A body is moving with constant velocity, then what will be the acceleration of that body?
Question 21.
Write the S.I unit of force.
Question 22.
On what factor the inertia of an object depends?
Question 23.
Express the second law of motion of newton in the context of the equation of momentum.