Energy & Motion Quiz

A reference point is a fixed, unmoving object that is used to determine the position or motion of other objects. It serves as a point of comparison and is often used in physics or navigation to establish a frame of reference. By being fixed and unmoving, a reference point provides a stable and consistent point of measurement, allowing for accurate observations and calculations. Therefore, the statement that a reference point is a fixed, unmoving object is true.

Inertia is the resistance to a change in motion. It is a property of matter that causes objects to resist changes in their velocity or direction. An object with more inertia will require more force to change its motion compared to an object with less inertia. This concept is described by Newton's first law of motion, which states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and direction, unless acted upon by an external force.

The equation Force = Mass x Acceleration is a direct representation of Newton's 2nd Law of Motion. This law states that the force acting on an object is directly proportional to its mass and the acceleration it experiences. In other words, the greater the force applied to an object, the greater its acceleration will be, and vice versa. This equation is a fundamental principle in understanding the relationship between force, mass, and acceleration in the context of motion.

Speed is the correct answer because it refers to the distance an object moves in a certain amount of time. It is a scalar quantity and does not take into account the direction of motion. Speed is calculated by dividing the distance traveled by the time taken. It is commonly used to describe how fast an object is moving without specifying the direction.

According to the 1st Law of Motion, also known as the law of inertia, an object at rest will stay at rest and an object in motion will stay in motion with the same speed and direction unless acted upon by an external force. In this scenario, Larry's cell phone was at rest on the dashboard. When Larry suddenly applied the brakes, the car came to a sudden stop, but the cell phone continued to move forward due to its inertia, crashing into the windshield and breaking it. This demonstrates the concept of inertia described by the 1st Law of Motion.

Velocity is the correct answer because it refers to the rate at which an object moves in a specific direction. It is a vector quantity that takes into account both the speed and direction of an object's motion. Acceleration, on the other hand, refers to the rate at which an object's velocity changes over time, while speed only indicates how fast an object is moving without considering its direction. Therefore, velocity is the most appropriate term to describe the rate an object moves in a given direction.

The given scenario best describes the 2nd Law of Motion. According to this law, the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. In this case, Ross applies the same force to both the soccer ball and the bowling ball. Since the soccer ball travels farther, it implies that it has less mass compared to the bowling ball. This aligns with the 2nd Law of Motion as the acceleration of an object is greater when the force applied to it is constant and its mass is smaller.

The given scenario describes the 3rd Law of Motion, also known as the Law of Action-Reaction. According to this law, for every action, there is an equal and opposite reaction. When Mary pushes against the ground with her rollerblades, the ground exerts an equal and opposite force on her, propelling her forward. This is why she is able to roll forward.

Momentum is determined by the mass & velocity of an object.

Potential energy and kinetic energy are both types of mechanical energy. Potential energy is the energy possessed by an object due to its position or condition, such as the energy stored in a stretched spring or a raised object. Kinetic energy, on the other hand, is the energy possessed by an object due to its motion, such as the energy of a moving car or a swinging pendulum. Therefore, both potential energy and kinetic energy fall under the category of mechanical energy.