Telangana SCERT Class 9 Physical Science Chapter 2 Solution – Matter Around Us. Here in this post we provides Class 9 Physical Science Matter Around Us Telangana State Board Solution. Telangana State Board English Class IX Medium Students can download this Solution to Solve out Improve Your Learning Questions and Answers.
Telangana State Board Class 9 Physical Science Chapter 2 Matter Around Us Solution:
Chapter: – 2
Reflections on concepts
1) Distinguish between speed and velocity. (AS1)
Ans: – The speed and velocity are different things like the rate of change of displacement is known as the speed whereas the covering a unit place with unite of times is known as the speed. The speed is scalar quantity and the velocity is vector quantity.
2) Briefly explain about constant acceleration?
Ans: – The constant velocity is determined by the ratio of the rate of change of velocity with the time. In this the velocity as well as the time changes with the increases of velocity or times.
3) How can you say that a body is in motion? Is it a common property? (AS1)
Ans: – The body which is in position always try to maintain its position and the body which is moving try to remain its state this state is not changing if we not apply the forces on it. So, the common property are different things like changing of its sates by forces.
4) Are average speed and average velocity same? If not explain why? (AS1)
Ans: – The average velocity and the average speed are different things. The rate of change of velocity with time is known as the velocity where are the ratio of distance to time is known as speed. The displacement may be zero but the distance not be zero.
5) How do you measure instantaneous speed? (AS1)
Ans: – The instantaneous speed is different from the average speed. In an instantaneous speed the ratio of distance to time is measure at a certain point but average this calculation are different.
6) Explain acceleration with an example? (AS1)
Ans: – The acceleration is the rate of change of velocity with the times. For example, if the velocity of car is 10 m/s and the time for taking the car in a certain place is 5 then its acceleration is 2m/s.
Application of Concepts
1) In the given figure distance vs time graphs showing motion oftwo cars A and B are given. Which car moves fast? (AS1)
Ans: – As we can see in the image of the distance time graph that the slop of A is high as compared to the B then the speed of car A will be maximum than the car B.
2) A train of length 50m is moving with a constant speed of 10m/s.Calculate the time taken by the train to cross an electric poleand a bridge of length 250 m.
Ans: – The speed= distance/time.
As in case 1 distance is 50m and speed is 10m/s.
So, time is (50/10=5) 5 second.
In the second case time is (250 +50)/10 = 300/10=10 second.
3) Draw the distance vs time graph when the speed of a body increases uniformly. (AS5)
4) Draw the distance – time graph when its speed decreases uniformly. (AS5)
5) What is the average speed of a Cheetah that sprints 100m in 4sec.? What if it sprints 50m in 2sec ?
Ans: – The average speed = total distance / total time.
So average speed of cheetah is = (100/4=25) 25 m/s.
And if it sprints in 50m in 2 second then average speed is (50/20 = 25) 25 m/s.
6) A car travels at a speed of 80 km/h during the first half of its running time and at 40 km/h during the other half. Find the average speed of the car.
Ans: – Average speed = total distance/ total time.
So, the average speed in this case is,
(80 + 40)/ (1+1) = 60m/s.
7) Particle covers 10m in first 5s and 10m in next 3s. Assuming constant acceleration. Find initial speed, acceleration and distance covered in next 2s. (AS7)
Higher Order Thinking questions
1) When the velocity is constant, can the average velocity over any time interval differ from instantaneous velocity at any instant? If so, give an example; if not explain why.(AS2)
Ans: – The average velocity is different from the instantaneous velocity. The ratio of total distance with the total time is known as the average velocity. The instantaneous velocity is the velocity of a moving object at a particular time or at a certain time so we see that this two are different things one states the velocity at a time but average velocity is the ratio of total distance and total times.
2) You may have heard the story of the race between the rabbit and tortoise. They started from same point simultaneously with constant speeds. During the journey, rabbit took rest somewhere along the way for a while. But the tortoise moved steadily with lesser speed and reached the finishing point before rabbit. Rabbit wakeup and ran, but rabbit realized that the tortoise had won the race. Draw distance vs time graph for this story. (AS5)
Multiple choice questions
1.) The distance travelled by an object in a specified direction is
(a) Speed (b) Displacement
(c) Velocity (d) Acceleration.
Ans: – Option (b) Displacement.
2.) If an object is moving with constant velocity, then the motion is
(a) Motion with Non uniform acceleration
(b) Motion with Uniform Acceleration
(c) Uniform Motion (d) Non uniform Motion.
Ans: – option (b).
3.) If there is change in the velocity of the object then the state of object with respectto motion is
(a) State of Constant Speed (b) State of Constant velocity
(c) State of Uniform Motion (d) State of Non uniform Motion.
Ans: – Option (d).
4.) If the acceleration of a moving object is constant then the motion is saidto be
(a) Motion with Constant Speed.
(b) Motion with Uniform Acceleration
(c) Motion with Uniform Velocity.
(d) Motion with Non-Uniform acceleration.
Ans: – option (b).