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Acceleration due to Gravity on Earth
Newton's second law is closely related to his first law of motion. It mathematically gives the cause-and-effect relationship between force and changes…
Consider a lady pushing a luggage cart as she moves. The external force exerted by her accelerates the cart in the direction of the applied force.
If she pushes with a greater force, the cart will move faster. To stop the cart, she needs to apply an external force in the direction opposite to her motion.
If she places more luggage on the cart, the same force produces a smaller acceleration in the direction of the net external force.
Compiling these, we get Newton's second law of motion, which states that an object accelerates proportionally and in the direction of the net external force and inversely to its mass.
Or, the net external force acting on an object is the product of its mass and its acceleration. All accelerating objects follow Newton's second law.
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Q1: What is acceleration due to gravity on Earth?
Acceleration due to gravity is the rate at which objects accelerate toward Earth's surface when falling freely under gravitational force alone. On Earth, this value is approximately 9.8 meters per second squared (m/s²). This constant applies to all objects regardless of mass, making it a fundamental constant in physics and mechanics.
Q2: Why does gravitational acceleration remain constant near Earth's surface?
Gravitational acceleration is constant near Earth's surface because the gravitational force acting on an object is proportional to its mass, and this force divided by mass yields a constant value. The distance from Earth's center remains relatively unchanged at the surface, so the acceleration remains approximately 9.8 m/s² for all objects in free fall.
Q3: How does mass affect an object's acceleration due to gravity?
Mass does not affect an object's acceleration due to gravity. Although gravitational force increases with mass, the acceleration remains constant at 9.8 m/s² because force and mass are proportionally related. This means a feather and a bowling ball accelerate at the same rate when falling freely in a vacuum.
Q4: What is the relationship between weight and gravitational acceleration?
Weight is the gravitational force exerted on an object and is calculated by multiplying mass by gravitational acceleration (W = mg). Since gravitational acceleration on Earth is 9.8 m/s², an object's weight increases proportionally with its mass. Weight varies with location, while mass remains constant.
Q5: How does altitude affect gravitational acceleration on Earth?
Gravitational acceleration decreases slightly with increasing altitude because distance from Earth's center increases. At higher elevations, objects experience slightly less gravitational acceleration than the standard 9.8 m/s² at sea level. This effect becomes more pronounced at extreme altitudes, such as in space or on mountains.
Q6: Why is gravitational acceleration important in mechanical engineering calculations?
Gravitational acceleration is essential for calculating forces, motion, and energy in mechanical systems. Engineers use the 9.8 m/s² value to determine structural loads, design safety systems, and predict object motion. Accurate gravitational acceleration values ensure reliable predictions of system behavior and component performance.