What is the metric unit of weight? How is this determined?
The Correct Answer and Explanation is :
The metric unit of weight is the newton (N). Weight is the force exerted by gravity on an object, and in the metric system, force is measured in newtons, named after Sir Isaac Newton.
Explanation:
To understand why the newton is the metric unit of weight, it’s important to differentiate between mass and weight. Mass is the amount of matter in an object, and it is measured in kilograms (kg) in the metric system. Mass does not change based on location—whether you’re on Earth, the Moon, or elsewhere in space, the mass of an object remains constant.
Weight, however, is a force that depends on both the mass of an object and the gravitational acceleration at the location where the object is. Weight is determined by the formula:
[
W = m \times g
]
Where:
- ( W ) is the weight (force) in newtons (N),
- ( m ) is the mass in kilograms (kg),
- ( g ) is the acceleration due to gravity, which on Earth is approximately 9.81 m/s².
The newton is defined as the force required to accelerate a one-kilogram mass by one meter per second squared. In other words, 1 N is the force needed to move a 1 kg object at an acceleration of 1 m/s². Since weight is a force, and it depends on gravity, it is expressed in newtons.
For example, if an object has a mass of 10 kg on Earth, its weight would be:
[
W = 10 \, \text{kg} \times 9.81 \, \text{m/s}^2 = 98.1 \, \text{N}
]
Thus, the weight of the object is 98.1 newtons.
In conclusion, weight is a force, and the unit of force in the metric system is the newton (N), which is determined by the object’s mass and the gravitational acceleration acting on it.