Analyse the statements and choose the correct answer:
Assertion (A): A particle moves along a circle.
Resertion (R-I ): speed is uniform.
(R-II ): Velocity is changing
Answer : D. Both are correct
A girl is swinging on a swing in sitting position. When the same girl stands up, the period of swing will
Answer : A. be shorter
A simple machine helps a person doing
Answer : B. the same amount of work with lesser force
The normal boiling point of a liquid is the temperature at which
Answer : D. the vapour pressure of the liquid is equal to the atmospheric pressure
the density of pure water will be
Answer : A. maximum at 4oC
If the depth of floatation of a ship changes when it sails from the Arabian sea to the Indian ocean, it is due to
Answer : D. change in density of sea-water