CBSE Class 9 Science Is Matter Around us Pure MCQs Set B

a) zero

b) 25 m/s

c) 24 m/s

d) none of these

Answer: zero

Question: If an object covering distances in direct proportion to the square of the time lapsed, then the acceleration is

a) constant

b) increasing

c) decreasing

d) none of these

Answer: constant

Question: Distance travelled by a freely falling body is proportional to

a) square of the time of fall

b) time of fall

c) square of the acceleration due to gravity

d) mass of the body

Answer: square of the time of fall

Question: The rate of change of displacement with time is

a) velocity

b) acceleration

c) speed

d) retardation

Answer: velocity

Question: Which of the following is not vector quantity?

a) Displacement

b) Average speed

c) Acceleration due to gravity

d) Retardation

Answer: Displacement

Question: If the time-displacement graph of a particle is parallel to the time-axis, then velocity of the particle is

a) zero

b) equal to acceleration of the body

c) unity

d) infinity

Answer: zero

Question: In the velocity-time graph, AB shows that the body has

a) initial velocity OA and is moving with uniform retardation

b) uniform speed

c) non-uniform retardation

d) uniform acceleration

Answer: initial velocity OA and is moving with uniform retardation

Question: In the given velocity-time graph, AB shows that the body has

a) none of these

b) uniform velocity throughout its motion and has zero initial velocity

c) uniform retardation

d) uniform acceleration

Answer: none of these

Question: If the displacement-time graph for the two particles A and B are straight lines inclined at angles of 30° and 60° with the time axis, then ratio of the velocities v_A: v_B will be

a) 3: 1

b) 1 : 3

c) 1 : 2

d) none of these

Answer: 3: 1

More Questions..........................

Question: In the given figure, velocity of the body at A is

a) zero

b) maximum

c) infinite

d) unity

Answer: zero

Question: The velocity-time graph for a body with nonuniform motion is a

a) curved line

b) straight line parallel to x-axis

c) straight line parallel to y-axis

d) none of these

Answer: curved line

Question: A motor ship covers the distance of 300 km between two localities on a river in 10 hrs downstream and in 12 hrs upstream. Find the flow velocity of the river assuming that these velocities are constant

a) 2.5 km/hr

b) 3.5 km/hr

c) 2.0 km/hr

d) 3 km/hr

Answer: 2.5 km/hr

Question: A stone is dropped into a well in which the level of water is h, below the top of the well. If v is velocity of sound, then time T after which the splash is heard is equal to

a)

b)

c)

d) None of these

Answer:

Question: A stone weighing 3 kg falls from the top of a tower 100 m high and buries itself 2 m deep in the sand. The time of penetration is

a) 0.09 sec

b) 2.1 sec

c) 0.9 sec

d) 1.3 sec

Answer: 0.09 sec

Question: The velocity of a body at any instant is 10 m/s. After 5 sec, velocity of the particle is 20 m/s. The velocity at 3 seconds before is

a) 4 m/sec

b) 7 m/sec

c) 6 m/sec

d) 8 m/sec

Answer: 4 m/sec

Question: A body covers 200 cm in the first 2 sec.and 220 cm in next 4 sec. What is the velocity of the body at the' end of 7th second?

a) 10 cm/sec

b) 40 cm/sec

c) 20 cm/sec

d) 5 cm/sec

Answer: 10 cm/sec

Question: A stone is thrown vertically upward with an initial velocity u from the top of a tower, reaches the ground with a velocity 3u. The height of the tower is

a) 4 u²/g

b) 3 u²/g

c) 9 u²/g

d) 6 u²/g

Answer: 4 u²/g

Question: Acceleration of a body projected upwards with a certain velocity is

a) – 9.8 m/s²

b) zero

c) insufficient data

d) 9.8 m/s²

Answer: – 9.8 m/s²

Question: The earth's radius is 6400 km. It makes one revolution about its own axis in 24 hrs. The centripetal acceleration of a point on its equator is nearly

a) 3.4 cm/s²

b) 340 cm/s²

c) 34 cm/s²

d) 0.34 cm/s²

Answer: 3.4 cm/s²

Question: The acceleration of a point on the rim of flywheel 1 m in diameter, if it makes 1200 revolutions per minute is

a)

b)

c)

d) none of these

Answer:

Question: If two bodies of different masses m₁ and m₂ are dropped from different heights h₁ and h₂, then ratio of the times taken by the two to drop through these distances is :-

a) √h₁ : √h₂

b) h₂/h₁

c) h₂ : h₁

d) None of these

Answer: √h₁ : √h₂

Question: Name the instrument used to measure instantaneous speed of a vehicle

a) Speedometer

b) Multicenter

c) Accelerator

d) Ammeter

Answer: Speedometer

Question: A ball is dropped on the floor from a height of 10 m. It rebounds to a height of 2.5 m. If the ball is in contact with the floor for 0.01 sec, then average acceleration during contact is :-

a) 2100 m/s²

b) 1400 m/s²

c) 700 m/s²

d) 400 m/s²

Answer: 2100 m/s²

Question: If a ball is thrown up with a certain velocity. It attains a height of 40 m and comes back to the thrower, then

a) total displacement is zero

b) total distance covered by it is zero

c) total displacement covered by it is 80 m

d) total distance covered by it is 40 m

Answer: total displacement is zero

Question: If a body of mass 0.10 kg is moving on circular path of diameter 1.0 m at the rate of 10 revolutions per 31.4 sec, then centripetal force acting on the body (n = 3.14) is

a) 0.2 Newton

b) 0.02 Newton

c) 2.0 Newton

d) 20.0 Newton

Answer: 0.2 Newton

Question: A phonograph record on turn table rotates at 30 rpm. The linear speed of a point on therecord at the needle at the beginning of the recording when it is at a distance of 14 cm from the centre is

a) 44 cm/sec

b) 52 cm/sec

c) 48 cm/sec

d) 22 cm/sec

Answer: 44 cm/sec

Question: The relationship between average speed, time and distance is

a) Average speed =total distance / total time

b) Time = average speed/distance

c) Distance = average speed × time

d) Average speed = distance × time

Answer: Average speed =total distance / total time

Question: A body moving along a circular path has

a) constant speed

b) constant velocity

c) no radial acceleration

d) no tangential velocity

Answer: constant speed

Question: A rubber ball dropped from a certain height

a) non-uniform speed

b) uniform speed

c) uniform retardation

d) uniform acceleration

Answer: non-uniform speed

Question: If the velocity of a body does not change, its acceleration is

a) zero

b) unity

c) infinite

d) none of these

Answer: zero

Question: When the distance an object travels is directly proportional to the length of time, it is said to travel with

a) constant speed

b) zero velocity

c) constant acceleration

d) uniform velocity

Answer: constant speed

Question: A body moves on three quarters of a circle of radius r. The displacement and distance travelled by it are:-

a)

b) displacement = r, distance = 3r

c)

d)

Answer:

Question: If two bodies of different masses m₁ and m₂ are dropped from different heights h₁ and h₂, then ratio of the times taken by the two to drop through these distances is :-

a) √h₁ : √h₂

b) h₂/h₁

c) h₂ : h₁

d) None of these

Answer: √h₁ : √h₂

Question: Name the instrument used to measure instantaneous speed of a vehicle

a) Speedometer

b) Multicenter

c) Accelerator

d) Ammeter

Answer: Speedometer

Question: A ball is dropped on the floor from a height of 10 m. It rebounds to a height of 2.5 m. If the ball is in contact with the floor for 0.01 sec, then average acceleration during contact is :-

a) 2100 m/s²

b) 1400 m/s²

c) 700 m/s²

d) 400 m/s²

Answer: 2100 m/s²

Question: If a ball is thrown up with a certain velocity. It attains a height of 40 m and comes back to the thrower, then

a) total displacement is zero

b) total distance covered by it is zero

c) total displacement covered by it is 80 m

d) total distance covered by it is 40 m

Answer: total displacement is zero

Question: If a body of mass 0.10 kg is moving on circular path of diameter 1.0 m at the rate of 10 revolutions per 31.4 sec, then centripetal force acting on the body (n = 3.14) is

a) 0.2 Newton

b) 0.02 Newton

c) 2.0 Newton

d) 20.0 Newton

Answer: 0.2 Newton

Question: A phonograph record on turn table rotates at 30 rpm. The linear speed of a point on therecord at the needle at the beginning of the recording when it is at a distance of 14 cm from the centre is

a) 44 cm/sec

b) 52 cm/sec

c) 48 cm/sec

d) 22 cm/sec

Answer: 44 cm/sec

Question: The relationship between average speed, time and distance is

a) Average speed =total distance / total time

b) Time = average speed/distance

c) Distance = average speed × time

d) Average speed = distance × time

Answer: Average speed =total distance / total time

Question: A body moving along a circular path has

a) constant speed

b) constant velocity

c) no radial acceleration

d) no tangential velocity

Answer: constant speed

Question: A rubber ball dropped from a certain height

a) non-uniform speed

b) uniform speed

c) uniform retardation

d) uniform acceleration

Answer: non-uniform speed

Question: If the velocity of a body does not change, its acceleration is

a) zero

b) unity

c) infinite

d) none of these

Answer: zero

Question: When the distance an object travels is directly proportional to the length of time, it is said to travel with

a) constant speed

b) zero velocity

c) constant acceleration

d) uniform velocity

Answer: constant speed

Question: A body moves on three quarters of a circle of radius r. The displacement and distance travelled by it are:-

a)

b) displacement = r, distance = 3r

c)

d)

Answer: