Background and Motivation:
In the late 18th century, the scientific community was abuzz with questions about the nature of gravity. While Isaac Newton's law of universal gravitation had laid the foundation, the actual value of the gravitational constant (G) remained elusive. This constant is a fundamental parameter in physics, quantifying the strength of the gravitational force between two objects. Determining G was crucial for understanding the behavior of celestial bodies and the overall structure of the universe.
Enter Henry Cavendish, a brilliant but reclusive English scientist known for his meticulous experimental skills. Cavendish recognized the challenge and devised an ingenious experiment to measure the gravitational force between two objects directly.
Experimental Setup:
Cavendish's apparatus, designed by fellow scientist John Michell, consisted of:
Torsion Balance: A delicate wooden rod suspended horizontally by a thin wire. Two small lead spheres were attached to the ends of the rod.
Large Lead Spheres: Two much larger lead spheres, each about 350 pounds, were positioned near the smaller spheres.
Enclosure: The entire setup was enclosed in a wooden box to isolate it from air currents and other disturbances.
The Experiment:
Legacy:
Cavendish's experiment is hailed as a masterpiece of experimental physics. It stands as a testament to his scientific rigor and innovative spirit. The torsion balance technique he pioneered continues to be used in various scientific investigations, including the study of gravity waves and the search for dark matter.
Let me know if you'd like to explore any specific aspect of Cavendish's experiment in more detail!
B)
Newton's Law of Universal Gravitation:
The force of attraction between any two objects with mass is described by Newton's law of universal gravitation:
F = G * (m1 * m2) / r\u00b2
Where:
F is the force of attraction (in Newtons)
G is the universal gravitational constant (approximately 6.67430 x 10 \u207b \u2071\u00b9 N \u22c5 m \u00b2 /kg \u00b2 )
m1 and m2 are the masses of the objects (in kilograms)
r is the distance between the centers of the objects (in meters)
Calculation:
In our case:
m1 = m2 = 5 kg
r = 2.5 meters
Plugging these values into the formula:
F = (6.67430 x 10 \u207b \u2071\u00b9 ) * (5 kg * 5 kg) / (2.5 m) \u00b2
F = 2.66972 x 10 \u207b \u2071\u2070 Newtons
Result:
The force of attraction between the two 5 kg masses, 2.5 meters apart from their centers, is approximately 2.67 x 10 \u207b \u2071\u2070 Newtons . This is an extremely small force, as gravity is a relatively weak force compared to other fundamental forces like electromagnetism.