1.3 Forces & Free Body Diagrams

We can think of force as

• A hug or handshake between two objects.
• A push or pull acting upon an object due to its interaction with itself.
• A force field generated by the object.
• A push or pull acting upon an object due to its interaction with another object.

Select all true statements about gravity.

• It is a force.

• It only exists between the Earth and the objects on Earth.

• It exists between all objects.

• It is only noticable if all objects are massive.

• It is more noticable when at least 1 object is massive.

What is the normal force?

• The normal force is the force exerted by a surface to support the weight of an object resting on it.
• The normal force is the force of friction between two surfaces.
• The normal force is the force exerted by an object on a surface.
• The normal force is the force of gravity pulling an object downward.

What is static friction?

• Static friction is the force that causes objects to move at a constant speed
• Static friction is the force that prevents an object from moving along a surface.

• Static friction is the force that occurs between two objects in motion
• Static friction is the force that increases as the speed of an object increases

What is kinetic friction?

• Kinetic friction is the force that opposes the relative motion between two surfaces in contact when they are sliding against each other.
• Kinetic friction is the force that helps objects move smoothly without any resistance.
• Kinetic friction is the force that attracts objects towards each other.
• Kinetic friction is the force that increases the speed of objects in motion.

What is air resistance?

• Air resistance is the force that opposes the motion of an object through the air.
• Air resistance is the force that increases the speed of an object in the air.
• Air resistance is the force that attracts objects to the ground.
• Air resistance is the force that propels an object forward in the air.

What is tension?

• Tension is the force that is transmitted through a string, rope, cable, or wire when it is pulled tight by forces acting from opposite ends.
• Tension is the resistance of an object to motion.
• Tension is the pressure exerted by a gas in a closed container.
• Tension is the force that causes objects to float in water.

What is the SI unit used to measure force?

• Second (s)
• Meter (m)
• Newton (N)
• Kilogram (kg)

Name the missing force....

• weight force
• normal force
• frictional force
• tension force

Name the missing force...

• frictional force
• weight force
• thrust
• buoyant force