Physics
(a) Draw a diagram of a pulley system of velocity ratio 4. Calculate its mechanical advantage, if its efficiency is 90%.
(b) Why does a rope walker hold a long pole in his hands? Explain.
Related Questions
Shyam is trying to balance a meter rod on his finger as shown in the diagram. Two weight 50 gf and 200 gf at 40 cm and 95 cm respectively and his finger at 70 cm.
Find the anti-clock wise moment and clockwise moment.
(b) Find the weight of meter rod.
(a) State two characteristics that a medium should have for propagation of sound.
(b) A pendulum has a frequency of 4 vibrations per second. An observer starts pendulum and fires a gun simultaneously. He hears the echo from a cliff after 8 vibrations of pendulum. If the velocity of sound in air is 340 ms-1, then what is the distance between cliff and observer?
A ray is directed towards a lens as shown in the figure below. The lens is being depicted as a combination of a glass slab and two prisms.
Answer the following questions.
(a) Name the lens which is formed by this combination.
(b) What is PQ line called?
(c) Complete the ray diagram.
(d) The incident ray after refraction actually meet or appears to meet line PQ at a point. What is this point called?
(a) A truck and a car are running with the same speed on a highway. If the ratio of the kinetic energies is 25 : 12, then what is the ratio of their masses?
(b) Give two examples in which mechanical energy is conserved.