CBSE Class 9 Science Motion MCQs Set 03

Question: A body dropped from the top of a tower reaches the ground in 4 seconds. What is the height of the tower, if g = 10 m s^–2?
a) 78 m
b) 70 m
c) 80 m
d) 90 m
Answer: c

Question: For a body moving with a constant speed along a circular path, the direction of the velocity is
a) horizontal.
b) perpendicular to the radius.
c) along the tangent to the circle.
d) constant.
Answer: c

Question: A sprinter is running along the circumference of the sports ground with constant speed) Which of the following is changing?
a) Magnitude of acceleration
b) Distance covered
c) Force acting on the sprinter
d) Direction of motion
Answer: d

Question: Which is not the correct equation of motion?
a) s = ut + 1/2 at²
b) v² – u² = 2as
c) v = u – at
d) v – u = at
Answer: c

Question: A body falling freely under gravity shows a
a) uniform acceleration.
b) non-uniform acceleration.
c) uniform velocity.
d) variable velocity.
Answer: a

Question: For uniform motion
a) the distance–time graph is a straight line parallel to the time axis.
b) the speed–time graph is a straight line inclined to time axis.
c) the speed–time graph is a straight line parallel to time axis.
d) the acceleration–time graph is a straight parallel to time axis.
Answer: c

Question: The SI unit of retardation is
a) m s^–1
b) m s^–2
c) m s²
d) m
Answer: b

Question: If a body takes time t to complete one round of the circular path of radius r, then the speed of the body (v) is given by
a) v = πr × t
b) v = πr / t
c) 2 πr / t
d) 2πr × t
Answer: c

Question: A free-falling stone under the action of gravity exhibits a
a) uniform motion.
b) non-uniform motion.
c) zigzag motion.
d) curvilinear motion.
Answer: b

Question: The area under a speed–time graph represents a physical quantity which has the unit of
a) m
b) m²
c) m s^–1
d) m s^–2
Answer: b

Question: If a driver decreases the speed of a car from 25 m/s to 10 m/s in 5 seconds, the acceleration produced by the car is
a) –3 m s^–2
b) 3 m s^–2
c) 5 m s^–2
d) 7 m s^–2
Answer: a

Question: Which is a vector quantity?
a) Weight
b) Mass
c) Density
d) Volume
Answer: a

Question: For a uniformly retarded motion, the velocity–time graph is
a) a curve.
b) a straight line parallel to time axis.
c) a straight line perpendicular to time axis.
d) a straight line inclined to time axis.
Answer: d

Question: If a bus decreases its speed from 80 km/h to 60km/h, then its retardation is
a) 11.1 m s^–2
b) 1.11 m s^–2
c) –1.11 m s^–2
d) 111 m s^–2
Answer: b

Question: A car moving on a straight road is said to possess
a) rectilinear motion.
b) rotatory motion.
c) rotatory motion.
d) both rectilinear motion and rotatory motion
Answer: d

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

Question: At the maximum height, a body thrown vertically upwards has
a) velocity not zero but acceleration zero.
b) acceleration not zero but velocity zero.
c) both acceleration and velocity not zero.
d) both acceleration and velocity zero.
Answer: d

Question: The device fitted in an automobile to measure the distance travelled by it is
a) odometer.
b) speedometer.
c) hygrometer.
d) ticker tape timer.
Answer: a

Question: The magnitude of speed and velocity of a body is equal only if the body moves along a
a) straight line.
b) circular path.
c) zigzag path.
d) curved path.
Answer: a

Question: The distance–time graph of a body having non-uniform motion is a
a) straight line parallel to time axis.
b) straight line perpendicular to time axis.
c) curved line.
d) zigzag line.
Answer: c

Question: If a body covers equal distances in equal intervals of time in a particular direction, the body is said to have a
a) uniform velocity.
b) non-uniform speed
c) uniform speed
d) variable velocity.
Answer: a

Question: The average velocity of a body is equal to mean of its initial velocity and final velocity. The acceleration of the body is
a) variable.
b) zero.
c) negative.
d) uniform.
Answer: d

Question: A bus starting from rest moves with uniform acceleration of 0.1 m/s2 for 2 minutes. The distance covered by the bus is
a) 720 m.
b) 620 m.
c) 320 m.
d) 520 m.
Answer: a

Question: A body is moving along a circular path of radius r. The displacement of the body when it completes half arevolution is
a) 0
b) 2r
c) πr
d) 2πr
Answer: b

Question: The distance travelled by a body moving in a circular path is
a) πr²
b) 2πr
c) πr
d) 2πr²
Answer: b

Question: A stone tied to a thread and whirled in a circular path is an example of
a) circular motion.
b) rotatory motion.
c) rectilinear motion.
d) uniform circular motion.
Answer: d

Question: The slope of a speed–time graph gives
a) velocity.
b) acceleration.
c) displacement.
d) distance travelled
Answer: b

Question: A ship is moving at a speed of 56 km/h. One second later it is moving at 58 km/h, then its acceleration is
a) 72 km h^–2
b) 720 km h^–2
c) 7200 km h^–2
d) 7.2 km h^–2
Answer: c

Question: When a body travels in a straight line and its velocity changes by equal amounts in equal intervals of time, it is said to have
a) uniform velocity.
b) non-uniform acceleration.
c) uniform acceleration.
d) uniform speed
Answer: c

Question: A shot-put thrown by an athlete is said to be in
a) rectilinear motion.
b) rotatory motion.
c) curvilinear motion.
d) oscillatory motion.
Answer: c