What are the SI units of energy, momentum, force, angular momentum, and torque?
The correct answer and explanation is:
Correct Answers (SI Units):
- Energy: Joule (J)
- Momentum: Kilogram meter per second (kg·m/s)
- Force: Newton (N)
- Angular Momentum: Kilogram meter squared per second (kg·m²/s)
- Torque: Newton meter (N·m)
Explanation:
Each physical quantity has a specific SI unit based on how it is derived from the fundamental units of mass, length, and time. These quantities are essential in understanding motion, forces, and energy transformations in physics.
Energy is measured in joules (J). One joule is defined as the energy transferred when a force of one newton is applied over a distance of one meter. This means 1 J = 1 N·m. Energy appears in many forms, including kinetic energy, potential energy, and thermal energy. It is a scalar quantity and has no direction.
Momentum is measured in kilogram meter per second (kg·m/s). Momentum is the product of mass and velocity. It is a vector quantity, meaning it has both magnitude and direction. It plays a crucial role in collisions and the conservation of motion.
Force is measured in newtons (N). A newton is defined as the force required to accelerate a 1-kilogram mass by 1 meter per second squared. Therefore, 1 N = 1 kg·m/s². Force is a vector and is fundamental in Newton’s laws of motion.
Angular momentum has the unit kilogram meter squared per second (kg·m²/s). It is the rotational equivalent of linear momentum and depends on the object’s moment of inertia and its angular velocity. It is conserved in systems without external torques.
Torque is measured in newton meters (N·m). It represents a rotational force or moment. Although it has the same units as energy, torque is a vector quantity acting around an axis, while energy is scalar. Torque causes angular acceleration in rotating objects.
These SI units help standardize scientific communication and calculations across disciplines.