Physics Concepts for Grade 7

What is Newton's First Law of Motion?

• An object will accelerate indefinitely without any force.

• An object will change its direction only when a force is applied.

• An object will only move if a force is applied continuously.

• An object will remain at rest or in uniform motion unless acted upon by an external force.

Explain Newton's Second Law of Motion with an example.

• Newton's Second Law states that energy is conserved in a closed system.

• Newton's Second Law describes the relationship between velocity and time.

• An example of Newton's Second Law is a ball rolling down a hill without any force acting on it.

• Newton's Second Law of Motion is F = ma, where F is force, m is mass, and a is acceleration.

What does Newton's Third Law of Motion state?

• For every action, there is a proportional reaction.

• For every action, there is an equal and opposite reaction.

• The force of an object is equal to its mass times its velocity.

• An object in motion stays in motion unless acted upon by a force.

Define work in terms of physics.

• Work is the product of force and distance in the direction of the force.

• Work is the total mass of an object multiplied by its velocity.

• Work is the energy stored in an object.

• Work is the rate of doing energy.

How is energy related to work?

• Work is the absence of energy.

• Energy cannot be converted into work.

• Energy is the same as mass.

• Energy is the capacity to do work.

What is the formula for calculating kinetic energy?

• KE = m * v

• KE = 0.5 * m * v

• KE = m * v^2 / 2

• KE = 0.5 * m * v^2

What is potential energy? Give an example.

• A fish swimming in water has potential energy because it is in a liquid environment.

• An example of potential energy is a rock held at the top of a hill; it has gravitational potential energy due to its elevated position.

• A stretched rubber band is an example of potential energy due to its tension.

• A car moving at high speed has potential energy due to its motion.

What is the unit of force in the International System of Units?

• joule (J)

• newton (N)

• watt (W)

• pascal (Pa)

Describe the relationship between mass and acceleration in Newton's Second Law.

• Acceleration is independent of mass in all scenarios.

• Increasing mass always increases acceleration regardless of force.

• Mass and acceleration are directly proportional when force is constant.

• Mass and acceleration are inversely related when force is constant.

What is friction and how does it affect motion?

• Friction is a force that enhances motion, making objects move faster.

• Friction has no effect on motion and allows objects to move freely.

• Friction is only present in liquids and does not occur in solids or gases.

• Friction is a force that opposes motion, affecting how objects move by slowing them down or stopping them.