Gravitation
DEFINITION
Gravitational Constant
The gravitational constant (G) is a proportionality constant that appears in the equation for Newton's law of gravitation. The value of G is approximately equal to 6.67×10−11 Nm2kg−2. DEFINITION
Experimental method to determine the value of gravitational constant
The experimental setup performed by Cavendish is shown in the attached figure. Two masses are attached to the end of a horizontal suspended bar. Then, two large lead spheres are brought close to the small ones but on opposite sides. There is no net force on the bar but a non-zero torque acts on it caused due to gravitational force of attraction. This cause twisting of the suspended wire until a maximum angular displacement. At the point of maximum angular displacement, restoring torque is equal and opposite to the gravitational torque.
d2GMmL=τθ
where τ is the restoring couple per angle of twist and is constant for a given material.
No comments:
Post a Comment