Understanding Force and Friction

What are the two main types of forces?

• Centrifugal forces and centripetal forces

• Magnetic forces and electrical forces

• Contact forces and non-contact forces

• Frictional forces and gravitational forces

What does Newton's First Law of Motion state?

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

• An object will accelerate if no force is applied.

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

• An object will remain in motion indefinitely without any forces acting on it.

What is the force that opposes the motion of an object?

• Gravity

• Friction

• Momentum

• Inertia

Name one factor that affects the amount of friction between two surfaces.

• Surface color

• Temperature of the surfaces

• Weight of the objects

• Surface roughness

What is static friction?

• Static friction is the force that prevents two surfaces from sliding past each other.

• Static friction is the force that increases with the speed of sliding surfaces.

• Static friction is the force that allows surfaces to slide easily past each other.

• Static friction is the force that accelerates two surfaces apart.

What is kinetic friction?

• Kinetic friction is the force that increases with speed.

• Kinetic friction is the force that acts on stationary surfaces.

• Kinetic friction is the force that accelerates an object.

• Kinetic friction is the force opposing the motion of sliding surfaces.

How does the weight of an object affect friction?

• Friction is independent of the object's weight.

• Heavier objects slide more easily due to less friction.

• The weight of an object increases friction.

• The weight of an object decreases friction.

Can friction be both helpful and harmful? Give an example.

• Friction only occurs in solid materials, not liquids or gases.

• Friction is always harmful, like in a car crash.

• Yes, friction can be both helpful and harmful. An example is car tires providing grip (helpful) versus engine parts wearing out due to excessive friction (harmful).

• Friction has no effect on movement or speed.

What is the difference between sliding and rolling friction?

• Sliding friction is the resistance to motion when surfaces slide against each other, while rolling friction is the resistance when an object rolls over a surface.

• Rolling friction is always greater than sliding friction.

• Sliding friction involves no movement between surfaces.

• Sliding friction occurs only on rough surfaces.

In what everyday situation do we rely on friction?

• Walking or running.

• Using a treadmill

• Sliding on ice

• Driving a car