Is Matter Around Us Pure ? — Science STD 9 — Question

When a car driver travelling at a speed of 10m/s applies brakes and brings the car to rest in 20s, then retardation will be:

1. +2m/s²
2. -2m/s²
3. -0.5m/s²
4. +0.5m/s²

A body suffers retardation of 1ms⁻² means:

How many types of mechanical waves exist in physics?

Which of the following configuration will form a cation:

The maximum speed of vibrations which produce audible sound will be in:

1. Dry air.
2. Sea water.
3. Ground glass.
4. Human blood.

Two masses m and 2m are dropped from certain height ‘h’. Then on reaching the ground:

A man stands at one end of a long steel pipe hits it with a hammer. Another man standing at the other end of the pipe hear 2 seconds. This is because:

The fungus disease causing maximum death of poultry bird is:

What determine the nature of the path followed by the particle:

Which of the following does not possess the ability to do work not because motion?

1. A sparrow flying in the sky.
2. A sparrow moving slowly on the ground.
3. A sparrow in the nest on a tree.
4. A squiral going up a tree.