CBSE Class 9 Science Motion MCQs Set B

Question. The numerical ratio of displacement to distance for a moving object is:
(a) Always less than 1
(b) Equal to 1 or less than 1
(c) Always more than 1
(d) Equal to 1 or more than one

Question: m/s2 is the SI unit of -
(a) distance
(b) displacement
(c) velocity
(d) acceleration

Answer :  D

Question. A body is thrown vertically upward with velocity u, the greatest height h to which it will rise is____________
(a) u/g
(b) u2/2g
(c) u2/g
(d) u/2g

Answer :  B

Question. A car is travelling at a speed of 90 km/h. Brakes are applied so as to produce a uniform acceleration of – 0.5 m/s². Find how far the car will go before it is brought to rest?
(a) 8100 m
(b) 900 m
(c) 625 m
(d) 620 m

Answer :  C

Question. Speed of 90 km/h when expressed in m/s is
(a) 2.5
(b) 90000
(c) 250
(d) 25

Answer :  D

Question: The distance covered in time t by a body having initial velocity u and having a uniform acceleration a is given by s = ut + ½ at2. This result follows from -
(a) Newton’s first law
(b) Newton’s second law
(c) Newton’s third law
(d) None of these.

Answer :  D

Question. Name the instrument used to measure instantaneous speed of a vehicle
(a) multimeter
(b) ammeter
(c) speedometer
(d) accelerator

Answer :  C

Question. Area under a v – t graph represents a physical quantity which has the unit
(a) m2
(b) m
(c) m3
(d) m s–1

Answer :  B

Question. An object travels 20 m in 5 sec and then another 40 m in 5 sec. What is the average speed of the object?
(a) 6 m/s
(b) 2 m/s
(c) 12 m/s
(d) 0 m/s

Answer :  A

Question. When a car driver travelling at a speed of 10 m/s applies brakes and brings the car to rest in 20 s, then the retardation will be:
(a) + 2 m/s2
(b) − 2 m/s2
(c) − 0.5 m/s2
(d) + 0.5 m/s2

Answer :  D

Question. The slope of distance – time graph gives instantaneous.
(a) acceleration
(b) speed
(c) velocity
(d) Distance covered

Answer :  B

Question: A body moving along a straight line at 20 m/s undergoes an acceleration of -4 m/s2. After two seconds its speed will be -
(a) -8 m/s
(b) 12 m/s
(c) 16 m/s
(d) 28 m/s.

Answer :  B

Question. The Rate of change of displacement is called_________
(a) Velocity
(b) Deceleration
(c) Acceleration
(d) Speed

Answer :  A

Question: a particle moves with uniform positive acceleration. Its velocity-time graph will be
(a) a straight line parallel to the time axis
(b) a straight line inclined at an obtuse angle to the time axis
(c) a straight line inclined at an acute angle to the time axis
(d) none of these.

Answer :  C

Question: A person travels distance πR along the circumference of a circle of radius R. Displacement of the person is
(a) R
(b) 2R
(c) 2πR
(d) zero

Answer :  B

Question. The speed at any instant of time is known as
(a) velocity
(b) given speed
(c) average speed
(d) instantaneous speed

Answer :  D

Question. Which of the following situations are not possible?
(a) A body moving with constant acceleration but with zero velocity.
(b) A body moving horizontally with an acceleration in vertical direction
(c) A body moving with a constant velocity in an accelerated motion
(d) All of these

Answer :  C

Question. Which of the following statement is correct regarding velocity and speed of a moving body?
(a) Velocity of a moving body is always higher than its speed
(b) Speed of a moving body is always higher than its velocity
(c) Speed of a moving body is its velocity in a given direction
(d) Velocity of a moving body is its speed in a given direction

Answer :  D

Question. A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:
(a) 19 m
(b) 17 m
(c) 16 m
(d) 18 m

Answer :  A

Question. An object moves along a curved path. The following quantities may remain constant during its motion.
(a) speed
(b) velocity
(c) magnitude of acceleration
(d) Both 'a' and 'c'

Answer :  D

Question. Suppose a boy is enjoying a ride on a marry-go-round which is moving with a constant speed of 10 m/s. It implies that the boy is:
(a) At rest
(b) Moving with no acceleration
(c) In accelerated motion
(d) Moving with uniform velocity

Answer :  C

Question. A particle is moving in a circular path of radius r. The displacement after half a circle would be_______
(a) Zero
(b) π r
(c) 2 r
(d) 2π r

Answer :   C

Question. If the displacement of an object is proportional to square of time, then the object moves with________
(a) uniform velocity
(b) uniform acceleration
(c) increasing acceleration
(d) decreasing acceleration

Answer :   B

Question. Area under a v – t graph represents a physical quantity which has the unit
(a) m2
(b) m
(c) m3
(d) m s–1

Answer :   B