A.2 Forces and Momentum

Question 1

Forces

Answer 1

Interaction between bodies, either in contact or at a distance

Question 2

Free-body Diagrams

Answer 2

Represent forces on a body and determine the resultant force

Question 3

Resultant Force

Answer 3

The net force acting on a body, calculated by vector addition of all individual forces

Question 4

Gravitational Force

Answer 4

An attractive force between two masses

Question 5

Electric Force

Answer 5

Force between charged objects

Question 5

Magnetic Force

Answer 5

Force due to magnetic fields acting on magnetic materials or moving charged particles

Question 6

Normal Force

Answer 6

The force perpendicular to the surface that prevents objects from “falling” into each other

Question 7

Friction

Answer 7

The force opposing the relative motion or tendency of such motion of two surfaces in contact

Question 8

Tension

Answer 8

The force transmitted through a string, rope, cable, or wire when it is pulled tight by forces acting from opposite ends

Question 9

Elastic Force

Answer 9

The force exerted by an elastic object returning to its original shape

Question 10

Drag

Answer 10

The force opposing an object’s motion through a fluid

Question 11

Buoyancy

Answer 11

The upward force exerted by a fluid that opposes the weight of an immersed object

Question 12

First Law (Inertia)

Answer 12

An object remains in uniform motion unless acted upon by an external force

Question 13

Second Law (F=ma)

Answer 13

The force acting on an object is equal to the mass of the object multiplied by its acceleration

Question 14

Third Law (Action-Reaction)

Answer 14

For every action, there is an equal and opposite reaction

Question 15

Momentum

Answer 15

The product of an object’s mass and its velocity

Question 16

Impulse

Answer 16

Change in momentum of an object when a force is applied over time

Question 17

Conservation of Momentum

Answer 17

In a closed system, the total momentum before and after an event is the same

Question 18

Elastic Collision

Answer 18

A collision in which kinetic energy is conserved

Question 19

Inelastic Collision

Answer 19

A collision in which kinetic energy is not conserved, but total momentum is conserved

Question 20

Explosion

Answer 20

A rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases

Question 21

Centripetal Force

Answer 21

The force required to keep a body moving in a circular path, directed towards the center of the circle

Question 22

Circular Orbit

Answer 22

The motion of an object in a circular path at a constant speed.

Question 23

Centripetal Acceleration

Answer 23

Acceleration towards the center of a circular path