8th Grade Physics Practice Quiz

The speed of an object is calculated by dividing the distance traveled by the time it takes to travel that distance. This fundamental formula is essential for understanding motion in physics.

Gravity is the force that attracts objects toward the center of the Earth. It is responsible for the phenomenon of objects falling when dropped.

Solids maintain a fixed shape and volume due to the strong bonds between their particles. This characteristic distinguishes them from liquids and gases, which can change shape.

The ampere is the base SI unit for measuring electric current. It is a fundamental unit used in electrical measurements and circuit analysis.

Refraction is the change in direction of light as it passes from one medium to another due to a change in speed. This property is responsible for phenomena such as the apparent bending of a straw in water.

Newton's First Law, also known as the law of inertia, states that an object will maintain its state of motion unless acted upon by an external force. This means it either remains at rest or continues moving at a constant velocity.

Friction is a resistive force that acts between surfaces in contact, opposing their relative motion. It plays a key role in slowing down moving objects and converting kinetic energy into heat.

Work is defined as the product of the force applied and the distance moved in the direction of the force. This formula helps in understanding energy transfer within mechanical systems.

Kinetic energy is the energy of motion, calculated using the formula ½ mv². It quantifies the energy an object possesses because of its speed and mass.

A switch is used to open or close a circuit, thereby controlling the flow of electrical current. It serves as an essential component in manipulating how and when the circuit is active.

A battery stores chemical energy and converts it into electrical energy, supplying the voltage that drives current in a circuit. Its function is imperative for both portable and stationary electrical systems.

Average speed is calculated by dividing the total distance by the total time. Here, 60 km divided by 2 hours equals 30 km/h, which is the correct average speed.

According to Boyle's Law, at constant temperature, the pressure of a gas is inversely proportional to its volume. This means that reducing the volume leads to an increase in pressure.

Gravity is the force that pulls objects toward the Earth, causing a ball thrown upward to slow down, stop, and then accelerate downwards. This concept is a key part of understanding motion under the influence of gravity.

Density is a measure of how much mass is contained in a given volume, calculated by dividing mass by volume. This property is important for understanding material behavior in various physical contexts.

When an object is in free fall and starts from rest, its final velocity can be calculated by multiplying the acceleration due to gravity (g) by the time (t) it has been falling. This formula assumes that there is no air resistance.

Acceleration is calculated by taking the change in velocity and dividing it by the time taken. In this case, (30 m/s - 10 m/s) divided by 5 seconds equals 4 m/s².

The Equivalence Principle indicates that gravitational acceleration is independent of an object's mass when air resistance is negligible. This explains why, in a vacuum, heavy and light objects fall at the same rate.

The speed of a wave is determined by multiplying its frequency by its wavelength (v = f à - λ). With a frequency of 5 Hz and a wavelength of 2 meters, the wave travels at 10 m/s.

Cooling an object often causes its particles to move closer together, reducing the volume while the mass remains constant. Since density is defined as mass per unit volume, a decrease in volume results in a higher density.