CBSE Class 11 Physics Motion in a Straight Line MCQs Set B

Question: A car covers the first half of the distance between two places at 40 km/h and another half at 60 km/h.
The average speed of the car is
a) 40 km/h
b) 48 km/h
c) 50 km/h
d) 60 km/h.
Answer: b

Question: A body is moving along a straight line path with constant velocity. At an instant of time the distance travelled by it is S and its displacement is D, then
a) D < S
b) D > S
c) D = S
d) D £ S
Answer: c

Question: A ball is dropped from a high rise platform at t = 0 starting from rest. After 6 seconds another ball is thrown downwards from the same platform with a speed v. The two balls meet at t = 18 s. What is the value of v ? (Take g = 10 m/s²)
a) 75 m/s
b) 55 m/s
c) 40 m/s
d) 60 m/s
Answer: a

Question: The velocity of train increases uniformly from,20 km/h to 60 km/h in 4 hours. The distance travelled by the train during this period is
a) 160 km
b) 180 km
c) 100 km
d) 120 km
Answer: a

Question: A particle moves along a straight line such that its displacement at any time t is given by s = (t³ – 6t² + 3t + 4) metres. The velocity when the acceleration is zero is
a) 3 m/s
b) 42 m/s
c) –9 m/s
d) –15 m/s
Answer: c

Question: A car moves a distance of 200 m. It covers the first half of the distance at speed 40 km/h and the second half of distance at speed v. The average speed is 48 km/h.
The value of v is
a) 56 km/h
b) 60 km/h
c) 50 km/h
d) 48 km/h.
Answer: b

Question: Motion of a particle is given by equation s = (3t³ + 7t² + 14t + 8) m. The value of acceleration of the particle at t = 1 sec is
a) 10 m/s²
b) 32 m/s²
c) 23 m/s²
d) 16 m/s²
Answer: b

Question: A car runs at a constant speed on a circular track of radius 100 m, taking 62.8 seconds for every circular lap. The average velocity and average speed for each circular lap respectively is
a) 10 m/s, 0
b) 0, 0
c) 0, 10 m/s
d) 10 m/s, 10 m/s.
Answer: c

Question: The displacement x of a particle varies with time t as x = ae–at + bebt, where a, b, a and b are positive constants. The velocity of the particle will
a) be independent of b
b) drop to zero when a = b
c) go on decreasing with time
d) go on increasing with time.
Answer: d

Question: The motion of a particle along a straight line is described by equation x = 8 + 12t – t3 where x is in metre and t in second. The retardation of the particle when its velocity becomes zero is
a) 24 m s^–2
b) zero
c) 6 m s^–2
d) 12 m s^–2
Answer: d

Question: An athlete completes one round of a circular track of radius R in 40 sec. What will be his displacement at the end of 3 min. 20 sec ?
a) Zero
b) 2 R
c) 2 pR
d) 7 pR
Answer: a

Question: A bus is moving with a speed of 10 m s^–1 on a straight road. A scooterist wishes to overtake the bus in 100 s.
If the bus is at a distance of 1 km from the scooterist, with what speed should the scooterist chase the bus?
a) 40 m s^–2
b) 25 m s^–2
c) 10 m s^–2
d) 20 m s^–2
Answer: d

Question: Two bodies A (of mass 1 kg) and B (of mass 3 kg) are dropped from heights of 16 m and 25 m, respectively.
The ratio of the time taken by them to reach the ground is
a) 4/5
b) 5/4
c) 12/5
d) 5/12
Answer: a

Question: A particle moves a distance x in time t according to equation x = (t + 5)^–1. The acceleration of particle is proportional to
a) (velocity)^3/2
b) (distance)²
c) (distance)^–2
d) (velocity)^2/3
Answer: a

Question: If distance covered by a particle is zero, what can you say about its displacement?
a) It may or may not be zero
b) It cannot be zero
c) It is negative
d) It must be zero
Answer: d

Question: Which of the following is a one dimensional motion ?
a) Motion of snake
b) Motion of air particle
c) Motion of satellite
d) Motion of train running on a straight track
Answer: d

Question: The distance travelled by a body is directly proportional to the time taken. Its speed
a) increases
b) decreases
c) becomes zero
d) remains constant
Answer: d

Question: The slope of the tangent drawn on position-time graph at any instant is equal to the instantaneous
a) acceleration
b) force
c) velocity
d) momentum
Answer: c

Question: A particle moves in a straight line with a constant acceleration. It changes its velocity from 10 m s–1 to 20 m s^–1 while passing through a distance 135 m in t second. The value of t is
a) 12
b) 9
c) 10
d) 1.8
Answer: b

Question: A particle is thrown vertically upward. Its velocity at half of the height is 10 m/s, then the maximum height attained by it (g = 10 m/s²)
a) 8 m
b) 20 m
c) 10 m
d) 16 m.
Answer: c

Question: Choose the wrong statement from the following.
a) The motion of an object along a straight line is a rectilinear motion.
b) The speed in general is less than the magnitude of the velocity.
c) The slope of the displacement-time graph gives the velocity of the body.
d) The area under the velocity-time graph gives the displacement of the body.
Answer: b

Question: If a car at rest accelerates uniformly to a speed of 144 km/h in 20 s, it covers a distance of
a) 1440 cm
b) 2980 cm
c) 20 m
d) 400 m
Answer: d

Question: A particle starts its motion from rest under the action of a constant force. If the distance covered in first 10 seconds is S1 and that covered in the first 20 seconds is S2, then
a) S2 = 3S1
b) S2 = 4S1
c) S2 = S1
d) S2 = 2S1
Answer: b

Question: The total distance travelled by the body in the given time is equal to
a) the area which v– t graph encloses with displacement axis
b) the area which x – t graph encloses with time axis
c) the area which v – t graph encloses with time axis
d) the area which a – t graph encloses with axis
Answer: c

Question: A man throws balls with the same speed vertically upwards one after the other at an interval of 2 seconds. What should be the speed of the throw so that more than two balls are in the sky at any time ?
a) more than 19.6 m/s
b) at least 9.8 m/s
c) any speed less than 19.6 m/s
d) only with speed 19.6 m/s
Answer: a

Question: A body dropped from a height h with initial velocity zero, strikes the ground with a velocity 3 m/s. Another body of same mass dropped from the same height h with an initial velocity of 4 m/s. The final velocity of second mass, with which it strikes the ground is
a) 5 m/s
b) 12 m/s
c) 3 m/s
d) 4 m/s.
Answer: a

Question: The displacement of a body is zero. The distance covered
a) is zero
b) is not zero
c) may or may not be zero
d) depends upon the acceleration
Answer: c

Question: Which of the following can be zero, when a particle is in motion for some time?
a) Distance
b) Displacement
c) Speed
d) None of the options
Answer: b

Question: A car moving with a speed of 40 km/h can be stopped by applying brakes after atleast 2 m. If thesame car is moving with a speed of 80 km/h, what is the minimum stopping distance?
a) 4 m
b) 6 m
c) 8 m
d) 2 m
Answer: c

Question: A body dropped from top of a tower fall through 40 m during the last two seconds of its fall. The height of tower is (g = 10 m/s²)
a) 60 m
b) 45 m
c) 80 m
d) 50 m
Answer: b

Question: The position x of a particle with respect to time t along x-axis is given by x = 9t2 – t3 where x is in metres and t in seconds. What will be the position of this particle when it achieves maximum speed along the +x direction?
a) 54 m
b) 81 m
c) 24 m
d) 32 m.
Answer: a

Question: A particle moves along a straight line OX. At a time t (in seconds) the distance x (in metres) of the particle from O is given by x = 40 + 12t – t3. How long would the particle travel before coming to rest?
a) 16 m
b) 24 m
c) 40 m
d) 56 m
Answer: a

Question: A train of 150 metre length is going towards north direction at a speed of 10 m/s. A parrot flies at the speed of 5 m/s towards south direction parallel to the railways track. The time taken by the parrot to cross the train is
a) 12 s
b) 8 s
c) 15 s
d) 10 s
Answer: d

Question: A particle moves in straight line with velocity 6 m/s and 3 m/s for time intervals which are in ratio 1:2. Find average velocity.
a) 2 m/s
b) 3 m/s
c) 4 m/s
d) 5 m/s
Answer: c

Question: The displacement ‘x’ (in meter) of a particle of mass ‘m’ (in kg) moving in one dimension under the action of a force, is related to time ‘t’ (in sec) by t = x + 3. The displacement of the particle when its velocity is zero, will be
a) 4 m
b) 0 m (zero)
c) 6 m
d) 2 m
Answer: b

Question: A bus travelling the first one-third distance at a speed of 10 km/h, the next one-third at 20 km/h and at last one-third at 60 km/h. The average speed of the bus is
a) 9 km/h
b) 16 km/h
c) 18 km/h
d) 48 km/h.
Answer: c

Question: A ball is thrown vertically upward. It has a speed of 10 m/sec when it has reached one half of its maximum height. How high does the ball rise? (Take g = 10 m/s²)
a) 10 m
b) 5 m
c) 15 m
d) 20 m
Answer: a

Question: The slope of velocity-time graph for motion with uniform velocity is equal to
a) final velocity
b) initial velocity
c) zero
d) None of the options
Answer: c

Question: What will be the ratio of the distance moved by a freely falling body from rest in 4th and 5th seconds of journey ?
a) 4 : 5
b) 7 : 9
c) 16 : 25
d) 1 : 1.
Answer: b

Question: A car is moving along a straight road with a uniform acceleration. It passes through two points P and Q separated by a distance with velocity 30 km/h and 40 km/h respectively. The velocity of the car midway between P and Q is
a) 33.3 km/h
b) 20 2 km/h
c) 25 2 km/h
d) 35 km/h.
Answer: c

Question: A ball is thrown vertically downward with a velocity of 20 m/s from the top of a tower. It hits the ground after some time with a velocity of 80 m/s. The height of the tower is (g = 10 m/s²)
a) 360 m
b) 340 m
c) 320 m
d) 300 m
Answer: d

Question: What is the rate of change of velocity of an object in uniform motion ?
a) Always equal to zero
b) Always less than one
c) Always greater than one
d) Either less than or equal to one.
Answer: a

Question: A boy standing at the top of a tower of 20 m height drops a stone. Assuming g = 10 m s^–2, the velocity with which it hits the ground is
a) 10.0 m/s
b) 20.0 m/s
c) 40.0 m/s
d) 5.0 m/s
Answer: b

Question: The ratio of the numerical values of the average velocity and average speed of a body is
a) unity
b) unity or less
c) unity or more
d) less than unity
Answer: b

Question: The water drop falls at regular intervals from a tap 5 m above the ground. The third drop is leaving the tap at instant the first drop touches the ground. How far above the ground is the second drop at that instant?
a) 3.75 m
b) 4.00 m
c) 1.25 m
d) 2.50 m.
Answer: a

Question: The location of a particle has changed. What can we say about the displacement and the distance covered by the particle?
a) Neither can be zero
b) One may be zero
c) Both may be zero
d) One is +ve, other is –ve
Answer: a

Question: Consider the following statements and select the incorrect statements.
I. The magnitude of instantaneous velocity of a particle is equal to its instantaneous speed.
II. The magnitude of the average velocity in an interval is equal to its average speed in that interval.
III. It is possible to have a situation in which the speed of the particle is never zero but the average speed in an interval is zero.
IV. It is possible to have a situation in which the speed of particle is zero but the average speed is not zero.
a) II, III and IV
b) I and II
c) II and III
d) IV only
Answer: a

Question: A particle moves 2m east then 4m north then 5 m west. The distance is
a) 11 m
b) 10 m
c) –11 m
d) 5 m
Answer: a

Question: The numerical ratio of displacement to distance for a moving object is
a) always less than 1
b) always equal to 1
c) always more than 1
d) equal to or less than 1
Answer: d

Question: Select the incorrect statements from the following.
I. Average velocity is path length divided by time interval.
II. In general, speed is greater than the magnitude of the velocity.
III. A particle moving in a given direction with a nonzero velocity can have zero speed.
IV. The magnitude of average velocity is equal to the average speed.
a) II and III
b) I and IV
c) I, III and IV
d) I, II, III and IV
Answer: a