Understanding Forces and Motion

What are the four main types of forces?

• Frictional force

• Magnetic force

• Centrifugal force

• Gravitational force, electromagnetic force, strong nuclear force, weak nuclear force

Define gravity and give an example.

• Gravity is the speed at which objects fall to the ground.

• Gravity is the force that pushes objects away from each other.

• Gravity is a type of energy that powers the universe.

• Gravity is the force that attracts objects with mass towards each other, exemplified by an apple falling from a tree.

What is the difference between mass and weight?

• Mass is the weight of an object; weight is the mass of an object.

• Mass and weight are the same thing; they can be used interchangeably.

• Weight is the amount of matter; mass is the force of gravity on that matter.

• Mass is the amount of matter; weight is the force of gravity on that mass.

Explain Newton's First Law of Motion.

• An object will change its motion only if it is in a vacuum.

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

• An object will remain in motion only if it is on a flat surface.

• An object will accelerate unless a force is applied.

How does Newton's Second Law relate to acceleration?

• Mass has no effect on acceleration.

• Acceleration is inversely proportional to net force.

• Acceleration is independent of net force.

• Newton's Second Law relates to acceleration by stating that acceleration is directly proportional to the net force and inversely proportional to mass.

What does Newton's Third Law state about action and reaction?

• Every action has no reaction at all.

• For every action, there is a proportional reaction.

• For every action, there is a delayed reaction.

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

Calculate the speed of a car that travels 150 km in 3 hours.

• 30 km/h

• 100 km/h

• 75 km/h

• 50 km/h

If a runner completes a 400-meter lap in 50 seconds, what is their speed?

• 10 meters per second

• 12 meters per second

• 6 meters per second

• 8 meters per second

What is the difference between speed and velocity?

• Velocity measures distance only, not direction.

• Speed is scalar; velocity is vector (includes direction).

• Speed can be negative while velocity cannot.

• Speed is always greater than velocity.

Describe how friction affects motion.

• Friction increases the speed of moving objects.

• Friction has no effect on motion.

• Friction only occurs in liquids and gases.

• Friction opposes motion and can slow down or stop moving objects.