Case Study Questions Class 9 Science Chapter 8 Motion
CBSE Class 9 Case Study Questions Science Motion. Important Case Study Questions for Class 9 Exam. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Motion.
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CBSE Case Study Questions Class 9 Science – Motion
(1) Distance and displacement are two quantities that seem to mean the same but are different with different meanings and definitions. Distance is the measure of “how much distance an object has covered during its motion” while displacement refers to the measure of“how far the abject actually from initial place.” using this data answer following questions.
(i)Which of the following relation is always true when object moves in straight line
(a)distance is always equal to displacement
(b)distance is always greater than or equal to displacement
(c)distance is always lesser than or equal to displacement
(d)none of the above
(ii) Kapiltravels 20 km to North but then come back to South for 40 km to pick up a friend. Whatis kapil’s total distance?
(a) 60km
(b) 80km
(c) 20km
(d) none of the above
(iii) Rahul travels 20 km to East but then come back to West for 10 km. Find displacement.
(a) 30km
(b) 20km
(c) 10km
(d) none of the above
(iv) Define distance and displacement of particle.
(v) Write difference between distance and displacement
Answer key -1
(i) b
(ii) a
(iii) c
(iv) Distance and displacement are two quantities that seem to mean the same but are different with different meanings and definitions. Distance is the measure of “how much distance an object has covered during its motion” while displacement refers to the measure of “how far the abject actually from initial place.”
(v) difference between distance and displacement is given by
No. | Distance | Displacement |
1 | The complete length of the path between any two points is called distance | Displacement is the shortest length between any two point. |
2 | Distance is a scalar quantity | Displacement is a vector quantity |
3 | The distance can only have positive values. | Displacement can be positive, negative, and even zero. |
Case 2:
(2) Answer the following questions by observing following diagram
(i)What is distance and displacement when particle moves from point A to B?
(a)distance is equal to displacement
(b)distance is greater than and equal to displacement
(c)distance is lesser than and equal to displacement
(d)none of the above
(ii)What is Displacement when particle moves from point A to D?
(a) 15km
(b) 20km
(c) 10km
(d) none of the above
(iii) What is Displacement when particle moves from point A to C through A-B-C?
(a) 10km
(b) 20km
(c) 10√2 km
(d) none of the above
(iv) Find distance covered when particle moves in path ABCDA i.e. starts from A and ends at A?
(a) 10km
(b) 0km
(c) 40 km
(d) none of the above
(v) Find Displacement covered when particle moves in path ABCDA i.e. starts from A and ends at A?
(a) 10km
(b) 0km
(c) 40 km
(d) none of the above
ANSWER KEY-2
(i) a
(ii) b
(iii) c
(iv) c
(v) b
Case 3:
(3) The speed of an object is the distance covered per unit time,and velocity is the displacement per unit time.To specify the speed of anobject, we require only its magnitude while Velocity is the speed of an object moving in adefinite direction.
(i) S.I unit of speed is
(a) m/s
(b) s/m
(c) m/s2
(d) none of these
(ii) Which of the following is true
(a)speed is scalar
(b)velocity is vector
(c)both a and b
(d)none of these
(iii) To specify speed we require
(a)magnitude
(b)direction
(c)both magnitude and direction
(d)none of these
(iv) Define speed and velocity of particle.
(v)Differentiate between speed and velocity.
Answer key-3
(i) a
(ii) c
(iii) a
(iv)The speed of an object is the distance covered by object per unit time.Velocity is defined as the displacement by particle per unit time.
(v) Difference between speed and velocity.
No. | speed | Velocity |
1 | The speed of an object is the distance covered by object per unit time. | Velocity is defined as the displacement by particle per unit time. |
2 | Speed can never be negative or zero | Velocity can be zero, negative, or positive.
|
3 | Speed is Scalar quantity
|
Velocity is Vector quantity
|
Case 4:
(4)The speed of an object need not be constant. In most cases, objects will be in non-uniform
motion. Thereforewe describe the rate of motion of such objects in terms of their average speed. The average speed of an object is obtained by dividing the total distance travelled by the total time taken. That is, average speed =total distance travelled / total time taken. Answer the following.
(i)An object travels 20 m in 5 s and then another 20 m in 5s. What is the average speed in m/s of the object?
(a)4
(b) 5
(c) 6
(d) None of these
(ii) An object travels 20 m in 5 s and then another 40 m in 5s. What is the average speed in m/s of the object?
(a) 4
(b) 5
(c) 6
(d)None of these
(iii)A man starts walking from a point P on a circular field of radius 7 km and after 1 hour later he comes to same point P after one complete round. find his speed. (take pi=22/7)
(a) 30km/hr
(b) 40km/hr
(c) 44km/hr
(d) 33km/hr
(iv) A man travelled on square field of side 10m .he completed one round of field by taking time 2s, 3s 1s and 2s respectively for each side. Find his average speed.
(a) 4m/s
(b) 5m/s
(c) 6m/s
(d) 7m/s
(v) Define average speed.write its formula and SI unit
Answer key-4
(i) a
(ii) c
(iii) c
(iv) b
(v) The average speed of an object is obtained by dividing the total distance travelled by the total time taken. That is, average speed =total distance travelled / total time taken.Its SI unit is given by m/s.
Case 5:
(5) We know that the circumference of a circle of radius r is given by . If the body takes
tseconds to go once around the circular path of radius r, the speed v is given by
v=2πr/t
When an object moves in a circular path with uniform speed, its motion is called
uniform circular motion. Refer the paragraph and answer the following questions
(i) What happens when a body is moving with constant speed?
(a)acceleration is non uniform
(b)velocity is uniform
(c)velocity is changing
(d)none of these
(ii) Cyclist on circular track with constant speed is example of
(a)uniform circular motion
(b)nonuniform circular motion
(c)both a and b
(d)none of these
(iii) Which of the following changes whenbody performsuniform circular motion?
(a)speed
(b)direction of velocity
(c)both a and b
(d) none of these
(iv) Define uniform circular motion. Give 2 examples of uniform circular motion
(v) Give the name of device used for measurement of speed of rotation
Answer key -5
(i) c
(ii) a
(iii) b
(iv) When an object moves in a circular path with uniform speed, its motion is calleduniform circular motion. Rotation of hour hand of clock and motion of fan at constant speed are examples of uniform circular motion.
(v) Odometers and speedometers are two of the many instruments used to measure speed of rotation.
Plz put more difficult these all are very much easy.
But all over excellent
Yes we have think also it. This year we will put more hard.
Yes
A bit hard question may be helpful