To change the state of motion, a net non-zero external unbalanced force must be applied on the object. Calculate the initial and final momentum of the object. But, he made an incorrect statement as the system suffers a change in momentum because the momentum before the collision is equal to the momentum after the collision. Question 4: You have seen weather reports on television and in newspapers. Comment on this logic and explain why the truck does not move. In this case, the player applied a force to change the velocity of the ball.
Force exerted on the object is 50 N. Question 4: Explain the formation of clouds. Answer When the carpet is beaten, it is suddenly set into motion. Eventually, the content of carbon dioxide increases. Solution: i The chemicals are dumped into rivers or lakes from industries and factories. As a result, the velocity of the insect changes to a great amount.
Chapter 6 : Class 9 Biology Select one of the following to see the online solutions for chapter 6 as well as for download. We also have questions of what activities increases the carbon dioxide in the air and what are the effects of greenhouse gas?. Question 2: Name two biologically important compounds that contain both oxygen and nitrogen. Answer: The blowing away or washing away of land surface by wind or water is known as soil erosion. At the end of each chapter, a brief summary is provided for a quick recall. Answer: River is a major source of fresh water. Question 4: Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest? Question 12: Name the different states of water which is found in the water cycle.
Are organisms that live in water totally independent of soil as a resource? During their growth, lichens release certain substances, which cause the rock surface to powder down forming a thin layer of soil. The atmosphere of Venus and Mars are largely composed of carbon dioxide, which constitutes 95% — 97% of the total amount of gases. Due to this reason, the leaves fall down from the tree when shaken vigorously. When the air rises, it cools and expands. Question 9: What is the momentum of an object of mass m, moving with a velocity v? If action is always equal to the reaction, explain how a horse can pull a cart. This difference lies essentially in their compositions. When the vocal cords are tight and thin, the type or quality of voice is different Question 13.
This process is called hearing. If a body is at rest, then it tries to remain at rest. The amount of carbon dioxide on these planets can range from 95% to 97%. Akhtar said that since the motorcar was moving with a larger velocity, it exerted a larger force on the insect. Question 6: Is water an essential resource for living organisms? Calculate the total momentum just before the impact and just after the impact.
The ideas and concepts presented through the solved numerical problems and solutions to the in between exercises will provide the learners a set of tools with which they can understand about the scientific concept of work. It protects plants from external injury and infection. An increase in the content of such gases would lead to a situation of global warming. Simultaneously, a large amount of oxygen is released. Therefore, the static friction between the truck and the road is also very high. Answer: Almost all living organisms are dependent on soil.
Calculate the initial recoil velocity of the rifle. Protective tissues include epidermis and cork. Hence, each person applies a force of 240 N to push the motor car. As a result, a forward force is exerted on him. Answer: The methods of preventing or reducing soil erosion are: i Prevention of deforestation ii Plantation of trees — Question 1: What are the different states in which water is found during the water cycle? If the cost of painting is at the rate of Rs 20 per , Find.
Solution: Water is needed for living organisms for various reasons like i Water medium is the place where all the cellular processes take place. Hence, inertia of the stone is greater than that of a rubber ball. Other organisms are dependent on plants for their survival and carnivores feed on these organisms. What are the different means by which infectious diseases are spread? Answer When a fireman holds a hose, which is ejecting large amounts of water at a high velocity, then a reaction force is exerted on him by the ejecting water in the backward direction. It consists of thin walled living cells. Solution: Various physical, chemical and some biological processes break down the rocks over a period.
You will have to explain the reason behind how the atmosphere acts as a stabilizer for our planet. A train takes 6hrs to cover this distance. Question 3: What cause winds? Question 4: A batsman hits a cricket ball which then rolls on a level ground. Some key points to remember from the chapter is given below. The greater is the mass of the body; the greater is its inertia and vice-versa. Fill in the blanks with suitable words.