Abook with a mass of 2.5 kg falls from a high shelf in a library. at a height of 2.0 meters its velocity is 2 m/s. what is the mechanical energy of the book?

answers are:

5j
44j
49j
54j

 E=Ek+Ep = m*v^2/2 + m*g*h = 2.5*4/2 + 2.5*9.8*2 = 5+49=54J

therefore, the efficiency is:

Answer: buoyancy forceexplanation: in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.