Answer:

Explanation:
Natural length of the string is given as

length of the string while block is hanging on it

extension in length is given as

now we have strain in the string is given as



similarly we will have cross-sectional area of the string is given as

now the stress in the string is given as




Now Young's Modulus is given as



Answer:
Explanation: Newton's second law of motion pertains to the behavior of objects for which all existing forces are not balanced. The second law states that the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object. The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object. As the force acting upon an object is increased, the acceleration of the object is increased. As the mass of an object is increased, the acceleration of the object is decreased.
Stars form inside relatively dense concenstrations of interstellar gas and dust known as molecular clouds.
hope it helps
factorise 1/10^2 out of both.
add 1/4.5 to 1/9.4 .... common denominator 4.5x9.4
multiply result by 1/10^2
find reciprocal of result
phew !