Diversity In Living Organisms — Science STD 9 — Question

Identify the type of tissue in the following: skin, bark of tree, bone, lining of kidney tubule, vascular bundle.

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 suggested that 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 was moving 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. Comment on these suggestions.

Define average speed, write any one point of difference between average speed and average velocity.

Define mole. What are the two things that a mole represents?

If one mole of nitrogen molecules weights 28g, calculate the mass of one molecule of nitrogen in grams.

What is a proton? State its relative mass and charge.

In the following case, net force acting is zero? Also, identify the direction of force when.
A person pushes a door to hold it shut.

Draw a well labelled diagram of phloem.