motion and gravity

Question 1

Mass

Answer 1

the amount of matter in an object

Question 2

kilogram

Answer 2

the mass of1 liter of water

Question 3

Newtons first law of motion (inertia)

Answer 3

If no net (total) force acts on an object, its
velocity is constant

Question 4

Examples of newtons first law of motion

Answer 4

• A hockey puck glides across the ice
  at constant speed until it hits something
• A rocket in space will coast along a
  straight line at constant speed

Question 5

speed definition

Answer 5

rate at which an object
changes its position

Question 6

Example of speed

Answer 6

65 miles/hour
= 105 km/hr
= 29 m/s

Question 7

Velocity definition

Answer 7

speed PLUS direction of travel

Question 8

momentum definition

Answer 8

p = mass x velocity

Question 9

acceleration definition

Answer 9

rate at
which an object
changes its velocity

Question 10

Acceleration can involve:

Answer 10

(1) increase in speed
(2) decrease in speed,
OR
(3) change in direction.

Question 11

force

Answer 11

a push or pull acting on an
object, causing it to accelerate (i.e.
causing a change in momentum).

Question 12

examples of force

Answer 12

grav ity = pull
electrostatic attraction = pull
electrostatic repulsion = push
magnetic f orce = push or pul

Question 13

newtons second law of motion

Answer 13

If net f orce ≠ 0, the acceleration of an
object is proportional to and in the
direction of the f orce

Question 14

second law equation

Answer 14

Force = mass x acceleration
F = ma
Tells us what happens when f orces ARE present

Question 15

newtons third law

Answer 15

For every action, there is
an equal and opposite reaction

Question 16

example of third law

Answer 16

If A pushes (or pulls) B,
then B pushes (pulls) A,
with a f orce EQUAL in size,
exactly OPPOSITE in direction.
All f orces come in pairs

Question 17

Newton’s 3rd implies

Answer 17

conservation of momentum:
(Changes in momentum also come in pairs

Question 18

Gravity

Answer 18

an attractive force
between all pairs of massive objects

Question 19

More details about gravity

Answer 19

Universal law of grav itation”:
Works ev ery where, between
any pair of massiv e objects.
Gravity is the weakest of the f our
fundamental forces of nature

Question 20

The gravitational force
between two objects: equation

Answer 20

F = G(m1m2)/d^2

Question 21

equation values meanings for gravintational force

Answer 21

F = gravitational force
M1 = mass of one object
M2 = mass of other object
d = distance between centers of two objects
G = “universal constant of gravitation”

Question 22

Grav ity depends on

Answer 22

MASSES of objects
Double the mass
of one object:
Force 2x larger
Double the mass
of both objects:
Force 4x larger

Question 23

Grav ity depends INVERSELY

Answer 23

INVERSELY
on the Square of DISTANCE
between object

Double the distance
between objects:
Force ¼ as large
Halv e the distance
between objects:
Force 4x as large