* If gravitation suddenly stops* …… neglecting the rotation … if someone is standing on ground ….. will the normal reaction disappear?? If yes why? I want to know when

## Yarns made of the tiny straws of carbon called nanotubes have an astounding ability to twist as they contract, scientists have found

## Class XI CBSE – Revision Questions MCQ – Semester 1

- What is the gravitational field strength of a planet when the weight of a 100 kg astronaut is 400 N?

a) ¼ N kg^{-1 } b) 9.8 N kg^{-1} c) 4 N kg^{-1 } d) infinity

- The only natural satellite of the earth complete orbits in about

a) 24 days b) 27.3 days c) 30 days d) 365 1/4 days

- The satellite that revolves in a polar orbit is called

a) Natural Satellite b) Geostationary satellite c) Polar

## What is the difference between centre of gravity,centroid and centre of mass ?

Centroid is the geometric centre of a plane figure or object Centroid divides the shape into regions of equal moments. Centre of mass is the mean location of all masses in a system Centre of gravity is the point through which the w...

## A question from practical life situation

“I was hit in the head with a 10 lb 10 inch circular disc a truck ran over my ques is? If it launched from ground level traveled 18.3 feet and hit my head i’md im 6’3. At what speed was it traveling? if it weighs 10 lbs what was its weight really like when [...]