Physics Final Practice Quiz

The SI unit of force is the Newton. The other units measure energy, pressure, and power respectively.

Acceleration is defined as the rate at which velocity changes over time. It involves changes in both speed and direction, making it a vector quantity.

Objects in free fall near Earth's surface accelerate downward at about 9.8 m/s². This approximation ignores air resistance to focus solely on gravitational acceleration.

Newton's Third Law of Motion asserts that every action has an equal and opposite reaction. This principle explains the interactions between objects when forces are applied.

Speed is a scalar because it only has magnitude, whereas velocity, displacement, and force are vectors that include direction. Scalars are simpler measures that do not involve directional components.

Kinetic energy is calculated using the formula KE = 0.5 * m * v², where m is mass and v is velocity. This equation expresses how energy increases with the square of the speed.

Ohm's law defines the relationship between voltage, current, and resistance with the equation V = I * R. This foundational law is crucial for understanding electrical circuits.

The photoelectric effect shows that light can eject electrons from a metal surface, which supports its particle nature. This experiment was key to developing the quantum theory of light.

The conservation of momentum principle states that in an isolated system with no external forces, the total momentum remains constant. This principle is especially useful in analyzing collisions.

Friction opposes motion and transforms some of the kinetic energy into heat, thereby reducing the mechanical energy available for motion. This energy conversion is a common source of energy loss in mechanical systems.

A pulley system offers mechanical advantage by allowing a smaller force to lift a heavier load. It works by redistributing the applied force over a greater distance, effectively multiplying the force.

The wavelength of a wave can be determined by dividing the wave's speed by its frequency. This fundamental relationship connects the key properties of wave motion.

Uniform circular motion involves an object moving at a constant speed around a circle. Although the speed remains unchanged, the continual change in direction results in centripetal acceleration.

In a perfectly inelastic collision, where the colliding objects stick together, momentum is conserved even though kinetic energy may not be. This makes the conservation of momentum the primary principle for analyzing such collisions.

Free-body diagrams are used to clearly illustrate all the forces acting on a single object. This visual tool helps simplify complex problems by isolating the forces for further analysis.

The acceleration is calculated by dividing the change in velocity by time (10 m/s ÷ 5 s = 2 m/s²). Multiplying the acceleration by the mass (2 kg � - 2 m/s²) yields the applied force of 4 N.

The frictional force is found using the equation: friction = coefficient � - mass � - gravitational acceleration. Here, 0.2 � - 5 kg � - 9.8 m/s² equals 9.8 N.

The period of a simple pendulum depends on the length and the gravitational acceleration, but it is independent of the mass of the bob. Under ideal conditions with small angles, changes in amplitude do not significantly affect the period either.

The magnetic force on a charged particle is given by the Lorentz force equation F = q(v � - B), where the cross product determines both the magnitude and direction of the force. This formula is fundamental in understanding the interaction between charged particles and magnetic fields.

In an elastic collision between two identical masses with equal and opposite speeds, the objects essentially exchange velocities. Therefore, each object departs the collision with a speed equal to its initial speed.