Give any two reasons why da efficiency of any practical machine always lessthan 100%

The law of the conservation of momentum says that the total momentum of any closed and isolated system cannot

The period of a pendulum varies directly as the square root of the length of the pendulum and inversely as the square root of the acceleration due to gravity. find the period when the length is 144 cm and the acceleration due to gravity is 980 cm per second squared, if the period is 7pi seconds when the length is 289 cm and the acceleration due to gravity is 980 cm per second squared.

State the following: boyle's law and charle's law