Mechanical Properties of Solids — Physics STD 11 Science — Question

Can mechanical waves travel through vacuum?

Do all the drops of rain (big and small) reach the earth with same terminal velocity?

Which of the following examples represent periodic motion?
A freely suspended bar magnet displaced from its N-S direction and released.

If all the particle of a system lie in a cube, is it neccesary that the centre of mass be in the cube?

Write the two physical quantities whose dimensions are same.

In a real gas the internal energy depends on temperature and also on volume. The energy increases when the gas expands isothermally. Looking into the derivation of C_P - C_v = R, find whether C_P - C_v will be more than R, less than R or equal to R for a real gas.

It is easier to pull lawn roller than to push it. Why?

When a dielectric slab is gradually inserted between the plates of an isolated parallel-plate capacitor, the energy of the system decreases. What can you conclude about the force on the slab exerted by the electric field?

Explain why :
The climate of a harbour town is more temperate than that of a town in a desert at the same latitude.

Can a hot-wire ammeter be used to measure a direct current having a constant value? Do we have to change the graduations?