Read the following paragraph carefully and answer the questions.( 1 x 5 = 5marks)Akhtar, Kiran and Rahul were riding in a motorcar that was moving with a high velocity on an expressway when an insect hit the windshield and got stuck on the windscreen. Akhtar and Kiran started pondering over the situation. Kiran suggestedthat the insect suffered a greater change in momentum as compared to the change in momentum of the motorcar (because the change in the velocity of the insect was much more than that of the motorcar). Akhtar said that since the motorcar wasmoving with a larger velocity, it exerted a larger force on the insect. And as a result the insect died. Rahul while putting an entirely new explanation said that both the motorcar and the insect experienced the same force and a change in their momentum 12. Who suggested that the mass of insect is very small when compared to the mass of car hence it suffered a greater change in momentum.
Answers
Chemical, Physical and Biological Weathering
Weathering occurs one of three ways: through physical processes such as freezing and thawing, because of live organisms whose roots break rocks or through chemical processes that occur when carbon dioxide in the soil and air and mixes with water and specific minerals in rocks to form a weak acid that reduces rocks into silt, soil and sediment.
Chemical weathering typically increases as temperatures rise and rain falls, which means rocks in hot and wet climates experience faster rates of chemical weathering than do rocks in cold, dry climates.
Physical weathering occurs more often in cold climates, because the different minerals within rocks expand and contract at different rates when they are heated and cooled. Repeated heating and cooling cycles eventually cause rocks to fracture. Desert and mountain climates experience a wide range of temperatures from low to high during a day and night, which accounts for the breakdown of rocks known as physical weathering.
Biological weathering occurs when living organisms break up rocks. Tree roots, for example, can fracture rocks in the same way they buckle pavement. Warm, humid climates are most favorable to life. Contrast the rich diversity of life in a rainforest, for example, with the scarcity of life in the dry Sahara or the frigid Antarctic. Consequently, rates of biological weathering are most rapid in warm humid climates like those in tropical regions.
Rahul gave the correct reasoning and explanation that both the motorcar and the insect experienced the same force and a change in their momentum. As per the law of conservation of momentum.
When 2 bodies collide:
Initial momentum before collision
= Final momentum after collision
m1 u1+ m2 u2
= m1 v1+ m2 v2
The equal force is exerted on both the bodies but, because the mass of insect is very small it will suffer greater change in velocity.