Forces, Friction, and Gravity

What is the formula to calculate frictional force?

• Frictional force = coefficient of friction x normal force

• Frictional force = mass x acceleration

• Frictional force = distance / time

• Frictional force = work / energy

Name three factors that affect friction.

• Sound, light, and electricity

• Velocity, acceleration, and momentum

• Surface roughness, the force pressing the surfaces together, and the materials of the surfaces in contact.

• Temperature, color, and smell

What is the difference between weight and mass?

• Weight is the force exerted on an object due to gravity, while mass is the amount of matter in an object.

• Mass is the force exerted on an object due to gravity, while weight is the amount of matter in an object.

• Weight and mass are the same thing and can be used interchangeably.

• Weight is the amount of matter in an object, while mass is the force exerted on an object due to gravity.

What is the acceleration due to gravity on Earth?

• 10.25 m/s^2

• 7.93 m/s^2

• 5.67 m/s^2

• 9.81 m/s^2

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State Newton's first law of motion.

• An object in motion will eventually come to a stop on its own

• An object at rest will stay at rest, and an object in motion will stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

• An object at rest will start moving on its own

• An object in motion will change direction on its own

What is the relationship between force, mass, and acceleration according to Newton's second law?

• Force is equal to mass minus acceleration (F = m - a)

• Force is equal to mass plus acceleration (F = m + a)

• Force is equal to mass divided by acceleration (F = m/a)

• Force is equal to mass times acceleration (F = ma)

According to Newton's third law, for every action, there is an equal and opposite ____________?

• inaction

• unequal reaction

• overreaction

• reaction

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Explain the concept of free fall.

• Free fall is when an object is pushed upwards against gravity.

• Free fall is the motion of an object when gravity is the only force acting upon it.

• Free fall is the motion of an object when it is pulled by a magnetic force.

• Free fall is the movement of an object when it is propelled by a rocket.

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What is the SI unit of force?

• joule (J)

• meter (m)

• newton (N)

• kilogram (kg)