Physics
A ball of mass m is dropped freely from point A. It is given that AB = BC = CD = h. If the acceleration due to gravity at the given place is g, then what will be its
(a) potential energy at point A?
(b) kinetic energy at point C?
Related Questions
Pavel took an earthen pot which was filled with water up to its brim. The earthen pot was conical in shape and kept with its apex in downward direction.
(a) If the vertical height of the earthen pot is 12 cm, where does its centre of gravity lie?
(b) Pavel poured out all the water from the pot. How will its centre of gravity shift towards the open end or towards its apex?
(c) Pavel wanted to grow a plant in the given pot. So, he filled it completely again with some soil. What will be the new position of its centre of gravity?
The mass of the block P is 5 kg. It is to be moved along an inclined plane AC of length 8 m, which makes an angle of 30° with the horizontal. A force of 50 N is applied on the block to move it through the inclined plane AC, as shown in the diagram.
(a) What is the work done by the force along the inclined plane?
(b) Find the gain in potential energy of block P if it is directly lifted to C from the ground. (g = 10 ms-2)
(c) We know that potential energy is gained due to the work done on the body against gravity. Then, in this case, why is the work done on the block and the increase in the potential energy of the block different?
In a science exhibition, boys of a Secondary school made two types of periscopes. In one of the periscopes, ordinary glass was used as the reflecting material, while in the other, a prism was used. When Anushka put her eyes on the eyepiece of the periscope, she saw that the image formed in one of the periscopes was quite bright, while in the other, it was a little blurred.
(a) In which of the two periscopes, mirror or prism, Anushka saw the image brighter?
(b) Why is one of the images brighter than the other?
ABC is a glass block whose two sides, AB and BC, are at right angles to each other. A ray of light is incident on the surface AB, as shown in the diagram, and suffers total internal reflection before falling on the surface BC. Finally, the light ray emerges out along the surface BC.
(a) What is the angle of incidence at the surface AB?
(b) What is the critical angle for the glass block BC?
(c) What would happen to the critical angle if the temperature of the glass block is increased?