Physics
(a) What is a simple machine? State the principle of an ideal machine.
(b) A block and tackle pulley system has a velocity ratio 3. Draw a labelled diagram of this system. In your diagram, indicate clearly the points of application and the directions of the load and effort.
Machines
7 Likes
Answer
(a) A machine is a device by which we can either overcome a large resistive force (or load) at some point by applying a small force (or effort) at a convenient point and in a desired direction or by which we can obtain a gain in speed.
An ideal machine is that in which there is no loss of energy in any manner. Here, the work output is equal to the work input, i.e., its efficiency is 100%.
(b) Given,
V.R = n (number of pulleys) = 3
Hence, number of pulleys = 3
Below is a labelled diagram of the system indicating the points of application and the directions of load L and effort E:
Answered By
3 Likes
Related Questions
Monu pulls a toy car through a distance of 20 m on smooth and horizontal floor. The string field in Monu's hand makes an angle 60° with horizontal surface. If the force applied by the Monu be 10N,
(a) calculate the work done by Monu is pulling the car.
(b) If the string makes an angle 30° with the horizontal surface, then calculate work done.
A coolie of mass 55 kg move a load of 25 kg on his head upto 50 stairs, each of height 20 cm in 50 s. If g is 10 m/s2, then find
(a) gravitational force acting on coolie,
(b) work done by him
(c) his power in watt
(d) the gravitational force is increased by two times, then calculate the power.
(a) A wave has a frequency of 800 MHz and a wave length of 30 cm. Calculate velocity.
(b) A radio can tune in to any station in 17.5 MHz to 13.5 MHz band, what is the corresponding wavelength band?
Arrange α, β and γ-rays in ascending order with respect to their
(a) penetrating power
(b) ionising power
(c) biological effect