Matter in Our Surroundings — Science STD 9 — Question

Why helium and neon do not take part in chemical reactions?

Draw a velocity-time graph to show the following motion:
A car accelerates uniformly from rest for 5s ; then it travels at a steady’ velocity for 5s.

A girl weighing 25kg stands on the floor. She exerts a downward force of 250N on the floor. What force does the floor exert on her?

Why does steam cause more severe burns than boiling water?

A car is moving on a level road. If the driver turns off the engine of the car, the car’s speed decreases gradually and ultimately it comes to a stop. A student says that two forces act on the car which bring it to a stop. What could these forces be? Which of these two forces contributes more to slow down and stop the car?

Give an example of situation in which distance- is equal to displacement.

Give reason for the following observation:
The smell of hot sizzling food reaches us even from a considerable distance but to get the smell form cold food, we have to go close to it.