Help for these physics questions please

Question

Please help me. Thank you very much.

1. Indicate which statement is true(T) or false(F)? If false then change the word or phrase in bold underlined to make it true.

_____ The acceleration of gravity experienced by objects located near to (and far from) the earth depends upon the mass of the Earth.

_____ Increasing the mass of an object will increase the acceleration of gravity experienced by the object.

_____ Doubling the distance between an object and the earth’s centre will decrease the acceleration of gravity by a factor of two.

_____ If the mass of the Earth were doubled, then the acceleration of gravity on its surface would be quadrupled.

_____ If the mass of the Earth were quadrupled and the radius of the earth were doubled then the two changes would offset each other and the acceleration of gravity would remain the same.

2. Two spherical balls are placed so their centres are 255 cm apart. The force between the two balls is 2.80 x 10-12 N. What is the mass of each ball if one ball is 3.00 kg more than the mass of the other ball?

Answer 1

1. T

will not

four

doubled

T

1. r = 0.255 m, F = 2.8 X 10^-12 N, m₁ = x, m₂ = x + 3 kg

use F = Gm₁m₂ / r² rearrange to m₁m₂ = Fr² / G

x(x + 3) = (2.8 X 10^-12) (.255)² / 6.67 X 10^-11) = 0.476

x² + 3x = 0.476

` x² + 3x - 0.476 = 0

use quadratic formula to solve for x x = (-3 +/- sqrt [9 - (4)(1)(-..476)] / 2(1) = 0.15 kg

so m₁ = 0.15 kg and m₂ = 3.15 kg