Work, Energy, and Power — Physics STD 11 Science — Question

Read each statement below carefully and state, with reasons and examples, if it is true or false:
A scalar quantity is one that
Can never take negative values.

Answer the following :
The triple-point of water is a standard fixed point in modern thermometry. Why? What is wrong in taking the melting point of ice and the boiling point of water as standard fixed points (as was originally done in the Celsius scale)?

Two masses M, and M, separated by distance r start moving towards each other due to their own force of attraction. What will be the change in centre of mass?

A cloudy night is hotter than a clear sky night. Why?

Each side of a cube is measured to be 7.203 m. What are the total surface area and the volume of the cube to appropriate significant figures?

Give the magnitude and direction of the net force acting on.
A kite skillfully held stationary in the sky.

The gravitational force between two spheres is x when the distance between their centers is y. What will be the new force if the separation is made 3y?

Which physical quantity gives the area of the velocity-time graph?

A particle is in linear simple harmonic motion between two points, A and B, 10cm apart. Take the direction from A to B as the positive direction and give the signs of velocity, acceleration and force on the particle when it is:

At the mid-point of AB going towards A.

A ladder is at rest with its upper end against a wall and the lower end on the ground. Is the ladder more likely to slip, when a man stands on it at the bottom or at the top? Give reason.