Units and Measurements — Physics STD 11 Science — Question

What is the average friction force when a person has a usual 1km walk?

A stone of mass 0.25 kg tied to the end of a string is whirled round in a circle of radius 1.5 m with a speed of 40 rev./min in a horizontal plane. If the speed of the stone is increased beyond the maximum permissible value, and the string breaks suddenly, which of the following correctly describes the trajectory of the stone after the string breaks :
(a) the stone moves radially outwards.
(b) the stone flies off tangentially from the instant the string breaks.
(c) the stone flies off at an angle with the tangent whose magnitude depends on the speed of the particle?

What is the initial phase angle of a body starting simple hormonic motion from the terminal end?

State if the following statements is true or false. Give reasons for your answer:
In an elastic collision of two bodies, the momentum and energy of each body is conserved.

Can the carnot Engine be realized realistically?

From Kepler's second law and observations of the sun's motion as seen from the earth, we can conclude that the earth is closer to the sun during winter in the Northern hemisphere than during summer. Explain.

Which physical terms remain conserved in an inelastic collision?

Calculate the power of an electric engine which can lift 20 tonne of coal per hour from a mine 180m deep.

Read statement below carefully, and state, with reasons, if it is true or false:
The instantaneous speed of the point of contact during rolling is zero.

The breaking force for a wire is F. What will be the breaking forces for:

1. Two parallel wires of this size,
2. For a single wire of double thickness?