FORCES

Question 1

Force

Answer 1

It is a push or a pull exerted on one object by another object.

Question 2

Forces can change….

Answer 2

The velocity of the object (in magnitude and/or in direction)

Question 3

Contact force

Answer 3

It is a force that requires physical contact between two objects.

Question 4

Field force

Answer 4

It is a force that does not require physical contact between the two objects.

Question 5

External force

Answer 5

It is a force originated from outside of the object in which it is applied.

Question 6

Internal force

Answer 6

It is a force originated from inside of the object in which it is applied.
In human body, internal forces can be classified as active and passive.

Question 7

Active force

Answer 7

It is a force generated inside of the body by stimulated muscle (voluntarily or not)

Question 8

Passive force

Answer 8

It is a force generated inside of the body by tension in stretched periarticular connective tissues, including the intramuscular connective tissues, ligaments, and joint capsules.

Question 9

Compressive force

Answer 9

It is a force that shrinks the body.

Muscles do ONLY compressive forces.

Question 10

Tensile force

Answer 10

It is a force that elongates the body.

Question 11

Eccentric force

Answer 11

It is a force that generates a bending in the body creating compressive stress (internal force) on one side and tensile stress on the opposite side.

Question 12

Tangential force

Answer 12

It is a force parallel to the surface of the body.

Question 13

Net force

Answer 13

It is the sum of all the external forces action on the object.

Question 14

First law of Newton

Answer 14

An object at rest stays at rest and an object in motion stays in motion with constant velocity unless acted upon by a net external force.

Question 15

Second Law of Newton

Answer 15

If an object has a non-zero net force acting on it, it accelerates in the direction of the net force.

Question 16

Inertia

Answer 16

It is the tendency of a body to remain at rest or in motion with constant velocity.

Question 17

Mass

Answer 17

It represents the amount of matter in an object, and it is a measure of the inertia of the object.

Question 18

Weight

Answer 18

It is the force of gravityexerted on an object.

Question 19

Gravitational force

Answer 19

It is the force exerted by the Earth on an object.

Question 20

Third law of Newton

Answer 20

If an object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A.

Question 21

Normal force

Answer 21

It is a force perpendicular to the surface of contact.

Question 22

Frictional force

Answer 22

It is theforceresisting the relative motion of solid surfaces sliding against each other (or trying to do it).

Friction depends upon the nature of the two surfaces
and upon the degree to which they are pressed together.

The friction force applies in the plane of the surface of contact but opposes the motion (or intended motion) of an object.

Question 23

Theforce of static friction

Answer 23

It is a force between two surfaces thatprevents those surfaces from sliding across each other.

Question 24

Theforce of kinetic friction

Answer 24

It is a force that always opposes the sliding motion and tries toreduce the speed at which the surfaces slide across each other.

Question 25

Tension

Answer 25

It is a pulling force applied by a cord, wire, cable, string, rope…

Question 26

Distributed force system

Answer 26

It is a system in which the load is not uniformly distributed over the area of the surface of contact.

Question 27

Pressure

Answer 27

It is equal to total applied force perpendicular to the surface divided by the area of the surface over which the force is applied.