question_answer 57)

  How does the force of attraction between the two bodies depend upon their masses and distance between them? A student thought that two bricks tied together would fall faster than a single one under the action of gravity. Do you agree with his hypothesis or not? Comment.

Answer:

  The force of attraction between two bodies of masses , and and separated by distance r is given by Newton's universal law of gravitation i.e.,where, G is the universal constant in nature. This force is known as gravitational force. The gravitational force is directly proportional to the product of the masses of two bodies and inversely proportional to the square of the distance between them. All bodies fall with the same acceleration due to gravity whatever their masses have. i.e.,  (where M = Mass of the earth, R = Radius of the earth) and from the equation it is clear that, acceleration due to gravity (i.e., g) depends only on mass of the earth, the radius of the earth. So, two bricks tied together will not fall faster than a single bricks under the action of gravity. Hence, the hypothesis is not correct.