Ready to see how well you understand motion, energy, and forces? Dive into our free 8th grade physics quiz designed to challenge your knowledge and boost your confidence in class! Whether you're hunting for a physics quiz for 8th graders, eager to explore basic physics quiz questions, or love tackling a middle school physics quiz adventure, this is your moment to shine. Track your score, get instant feedback, and learn on the fly with engaging, bite-sized questions. Think you can ace it? Click to begin the 8th grade physics quiz now and don't miss our bonus 8th Grade Science Quiz for extra practice. Good luck - start today!
What is the SI unit of force?
Newton
Joule
Pascal
Watt
Force is measured in newtons (N), named after Sir Isaac Newton. It quantifies the interaction that changes an object's motion. Joules measure energy, pascals measure pressure, and watts measure power. Learn more.
Which of these is a scalar quantity?
Mass
Velocity
Force
Displacement
Scalars have only magnitude and no direction; mass is an example of a scalar. Velocity, force, and displacement are all vector quantities because they include direction. Understanding the difference helps in solving motion and force problems. Learn more.
What is the acceleration due to gravity on Earth (approximately)?
9.8 m/s²
10 m/s
9.8 N
9.8 kg
The standard acceleration due to gravity at Earth's surface is about 9.8 meters per second squared. This value indicates the rate at which objects accelerate downward when in free fall. Newtons and kilograms are units of force and mass, not acceleration. Learn more.
What is the formula for speed?
Distance divided by time
Time divided by distance
Distance times time
Mass times velocity
Speed is defined as the distance traveled divided by the time taken. It is a scalar quantity because it does not include direction. The other options either invert the relationship or combine unrelated quantities. Learn more.
A ball is thrown straight up with an initial speed of 20 m/s. Approximately how high will it rise? (Ignore air resistance.)
20 m
10 m
40 m
80 m
Using the kinematic equation v² = 2gh (with final speed v = 0 at the top), we get h = v²/(2g) = (20²)/(2·9.8) ? 20.4 m. Air resistance is neglected in this ideal calculation. This result matches answer choice 20 m. Learn more.
What is the mechanical advantage of an inclined plane?
Length divided by height
Height divided by length
Force times distance
Height plus length
Mechanical advantage (MA) of an inclined plane is the ratio of the length of the slope to its vertical rise (height). A longer ramp or smaller height requires less input force. The other options do not correctly reflect this simple machine relationship. Learn more.
In an electric circuit, what component opposes the flow of current?
Resistance
Voltage
Capacitance
Inductance
Resistance is the property of a material that resists the flow of electric current, measured in ohms (?). Voltage is the potential difference, while capacitance and inductance store energy in electric and magnetic fields, respectively. Ohm's law (V=IR) relates voltage, current, and resistance. Learn more.
If a sound wave has a frequency of 500 Hz, what is its period?
0.002 s
0.2 s
2 s
0.5 s
The period (T) of a wave is the inverse of its frequency (f), so T = 1/f = 1/500 Hz = 0.002 seconds. This is the time for one complete cycle of the wave. The other choices are common mistakes from incorrect inversion or unit errors. Learn more.
How much work is done when a force of 10 N moves an object 5 m in the direction of the force?
50 J
15 J
2 J
500 J
Work is defined as the product of force and displacement in the direction of the force: W = F · d = 10 N · 5 m = 50 J. The joule (J) is the SI unit for work or energy. The other values result from incorrect multiplication or unit confusion. Learn more.
What is the mass of an object weighing 20 N on Earth?
2.04 kg
0.51 kg
20 kg
196 kg
Weight (W) equals mass (m) times gravitational acceleration (g): W = mg. Rearranging gives m = W/g = 20 N ÷ 9.8 m/s² ? 2.04 kg. The other options come from mixing units or misplacing the decimal. Learn more.
A 12 V battery is connected to a series circuit with resistors of 4 ? and 6 ?. What is the total current through the circuit?
1.2 A
0.5 A
2.0 A
72 A
In a series circuit, resistances add: R_total = 4 ? + 6 ? = 10 ?. Using Ohm’s law I = V/R gives I = 12 V ÷ 10 ? = 1.2 A. The large number 72 A would only arise if the total resistance were much smaller. Learn more.
To balance a seesaw, a child of weight 60 N sits 0.5 m from the pivot. How far from the pivot must a 15 N child sit on the opposite side?
2 m
0.125 m
0.5 m
1 m
Torque equilibrium requires weight1 × distance1 = weight2 × distance2. So 60 N × 0.5 m = 15 N × x, giving x = (60 × 0.5) / 15 = 2 m. The shorter distances come from arithmetic mistakes. Learn more.
When light enters water from air at an angle, it bends. Using Snell’s law with n_water = 1.33, what is the approximate angle of refraction if the incident angle is 30°?
22°
30°
45°
60°
Snell’s law states n?·sin?? = n?·sin??. Here, sin?? = (1·sin30°)/1.33 ? 0.5/1.33 ? 0.375, so ?? ? 22°. The other angles don't satisfy this relation. Learn more.
A car travels in a circular path of radius 50 m at a constant speed of 20 m/s. What is its centripetal acceleration?
8 m/s²
0.8 m/s²
400 m/s²
2.5 m/s²
Centripetal acceleration is given by a_c = v²/r = (20 m/s)² ÷ 50 m = 400 ÷ 50 = 8 m/s². The smaller values come from misplacing a decimal or using the wrong formula. Learn more.
A 2 ? resistor in series with a 3 ? resistor is connected in parallel with a 6 ? resistor across a 12 V battery. What is the total current drawn from the battery?
4.4 A
2.0 A
3.0 A
1.1 A
First, the series resistors add: R_series = 2 ? + 3 ? = 5 ?. Then find the parallel combination with 6 ?: 1/R_eq = 1/5 + 1/6 = 11/30, so R_eq ? 2.727 ?. Finally, I_total = V/R_eq ? 12 V ÷ 2.727 ? ? 4.4 A. Learn more.
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Study Outcomes
Understand Fundamental Physics Concepts -
Grasp core ideas of motion, force, and energy to build a solid foundation for 8th grade physics quiz questions.
Apply Newton's Laws -
Use Newton's laws of motion to calculate forces, mass, and acceleration in real-world scenarios.
Solve Kinematics Problems -
Calculate speed, velocity, and acceleration values to analyze one-dimensional motion situations.
Analyze Basic Electric Circuits -
Interpret simple circuit diagrams and predict current flow using fundamental principles of voltage and resistance.
Evaluate Energy Transformations -
Identify and explain how energy changes form, such as potential to kinetic, in everyday examples.
Track Your Progress -
Use instant scoring and feedback features to pinpoint strengths and areas for improvement in your middle school physics knowledge.
Cheat Sheet
Newton's First Law (Inertia) -
According to MIT OpenCourseWare, an object at rest or in uniform motion stays that way unless a net external force acts on it. This concept, inertia, explains why you lunge forward when a car stops suddenly. Remember "objects resist change" to recall inertia easily.
Newton's Second Law (F = ma) -
NASA's educational resources define this law as F = ma, meaning force equals mass times acceleration. If you push two shopping carts with the same force, the lighter one accelerates more because it has less mass. Practice by calculating different masses and accelerations to master the relationship.
Conservation of Energy -
The National Science Teaching Association highlights that energy cannot be created or destroyed but transforms between kinetic (KE) and potential energy (PE). Use the equation KE = ½mv² and PE = mgh to calculate energy changes in a roller coaster. A handy phrase is "PE + KE = constant" for closed systems.
Ohm's Law and Circuits -
Per PhET simulations from the University of Colorado Boulder, Ohm's Law states V = IR, where voltage equals current times resistance. In a simple circuit, increasing resistance decreases current if voltage stays constant. Draw circuit diagrams and plug in different I, R, or V values to see the effects in action.
Interpreting Motion Graphs -
Purdue University's online physics lab shows that the slope of a distance-time graph gives speed, while the slope of a velocity-time graph gives acceleration. A curved line on a distance-time graph indicates changing speed. Practice sketching graphs from word problems to build confidence in reading real data.
