Crop Production and Management — Science STD 8 — Question

Gymnasts apply some coarse substance on their hands.

Two persons are applying forces on two opposite sides of a moving cart. The cart still moves with the same speed in the same direction. What do you infer about the magnitudes and direction of the forces applied?

Copper vessel in due course acquires a dull green coating.

An owl can see very well in the night.

An archer shoots an arrow in the air horizontally. However, after moving some distance, the arrow falls to the ground. Name the initial force that sets the arrow in motion. Explain why the arrow ultimately falls down.

You are provided with a mixture of petroleum and water. How will you separate the two?

John and Radha were classmates since childhood. When Radha became eleven years old, she developed a little swelling on her neck. She visited the doctor who started medication for her. After a few years, John also developed a slight protrusion on his throat. He got worried and went to the doctor. But, the doctor assured him that it was a normal feature in boys while they are growing up. Can you think of any reasons for the difference in diagnoses?

Why does the increased level of nutrients in the water affect the survival of aquatic organisms ?

Changes occuring in adolescent boys and girls are different.

The common water conducts electricity while distilled water does not.