Mass

Definition

Mass is a measure of the amount of matter in an object, commonly expressed in kilograms or grams. It plays a crucial role in understanding how objects interact through gravitational forces, momentum during collisions, and the influence on acceleration when subjected to external forces. Mass is a scalar quantity that is intrinsic to an object and does not change regardless of its location in the universe.

5 Must Know Facts For Your Next Test

1. Mass is a scalar quantity, meaning it only has magnitude and no direction, unlike weight, which is a vector.
2. In gravitational interactions, the greater the mass of an object, the stronger its gravitational pull on other masses.
3. During elastic and inelastic collisions, the conservation of momentum depends on the masses and velocities of colliding objects.
4. The normal force acting on an object resting on a surface is equal to the weight of that object, which is determined by its mass.
5. Mass remains constant regardless of where an object is located, whether on Earth, in space, or on another planet.

Review Questions

• How does mass affect gravitational attraction between two objects?
  • The gravitational attraction between two objects is directly proportional to their masses. According to Newton's law of universal gravitation, the force of attraction increases as either mass increases. This means that if you double one object's mass while keeping the other constant, the gravitational force between them also doubles. Thus, more massive objects have a stronger pull on each other compared to less massive objects.
• Compare and contrast elastic and inelastic collisions in terms of mass and momentum conservation.
  • In both elastic and inelastic collisions, the total momentum of the system is conserved. However, in elastic collisions, both momentum and kinetic energy are conserved. This means that after the collision, the total kinetic energy remains the same if you account for the masses and velocities of the colliding objects. In contrast, inelastic collisions conserve momentum but not kinetic energy; some energy is transformed into other forms like heat or sound. Mass plays a key role in determining how velocity changes after these collisions.
• Evaluate how mass influences acceleration according to Newton's second law of motion.
  • According to Newton's second law of motion, acceleration is inversely proportional to mass when a constant force is applied ($$F = m \cdot a$$). This means that if you apply the same force to two different masses, the object with less mass will experience greater acceleration than the heavier object. Therefore, understanding how mass affects acceleration helps explain why lighter objects move more quickly under identical forces compared to heavier ones.

Related terms

Weight: Weight is the force exerted on an object due to gravity, calculated as the product of mass and the acceleration due to gravity ($$W = m \cdot g$$).

Inertia: Inertia is the property of an object that resists changes in its state of motion, directly related to its mass; heavier objects have greater inertia.

Momentum: Momentum is the product of an object's mass and its velocity ($$p = m \cdot v$$) and is conserved in isolated systems during collisions.