Flash Card #9

Question 1

What is force?

Answer 1

push or pull; described by
strength

Question 2

What is the unit of force?

Answer 2

Newton (N)

Question 3

What is force represented as?

Answer 3

Force is represented as an arrow (with direction)
longer arrow ~ greater force

Question 4

What is net force?

Answer 4

combining forces

Question 5

When do unbalanced forces occur?

Answer 5

Unbalanced forces occurs when a net force is
present causing a change in the object’s
motion.

Question 6

When do balanced forces occur?

Answer 6

Balanced forces occurs when equal (strength)
forces are acting in opposite directions. The net
force is zero. Balanced forces does not change
the object’s motion.

Question 7

What is friction?

Answer 7

the force that two surfaces exert
on each other when they rub against each
other.

Question 8

What are the factors that affect friction?

Answer 8

1) weight
2) rough versus smooth surfaces
3) lubricants (oils, grease); ball bearings
4) surface area

Question 9

What are the four types of friction?

Answer 9

Static Friction, Sliding Friction, Rolling Friction, Fluid Friction

Question 10

What is Fluid friction

Answer 10

Friction when an object moves
through a fluid. To reduce friction, use oils &
lubricants; streamline.

Question 10

What is Static Friction?

Answer 10

friction that acts on objects that
are not moving. Static greater than sliding, rolling,
fluid friction.

Question 11

What is Rolling friction?

Answer 11

friction when an object rolls
across a surface. To reduce friction, use wheels or
ball bearings.

Question 11

What is Sliding Friction?

Answer 11

friction when two surfaces slide
over each other.

Question 12

How is friction helpful?

Answer 12

1] STOP
2] MOVE
3] WARMTH
4] FIRE

Question 13

How is friction harmful?

Answer 13

1] WEAR OUT PARTS
(watches, engines, shoes, clothing)
2] FIRE (reentry from space)
3] REDUCES EFFICIENCY

Question 14

What is gravity?

Answer 14

an attractive force between
objects containing mass.

Question 15

What are the factors of gravity?

Answer 15

Mass and Distance

Question 16

What is Mass?

Answer 16

amount of matter (atoms) in an object

Question 17

What is distance?

Answer 17

length between two points
increase mass ~ increase gravity
increase distance ~ decrease gravity

Question 18

What is Terminal Velocity?

Answer 18

maximum velocity of a
free falling object occurs when the force of air
resistance equals the weight of the object.
Terminal velocity represents balanced forces
where upward air resistance equals downward
gravity.

Question 18

What is Projectile motion?

Answer 18

an object that is thrown. A projectile
(with horizontal motion) will fall at the same rate as
any dropped object.

Question 19

What is free fall?

Answer 19

only gravity acting on a falling object. Objects
accelerate as they free fall because gravity is an unbalanced
force. In a vacuum, all objects in free fall accelerate at the
same rate regardless of their masses. Gravitational
acceleration near Earth is 9.8 m/s2.

Question 20

What is air resistance?

Answer 20

is a type of fluid friction as an object
falls through the air. Greater surface area of object ~
increase in air resistance ~ slower the object falls. Air
resistance increases as velocity increases.

Question 21

What are action and reaction pairings?

Answer 21

jumping
paddling

Question 21

What is Newton’s 1st Law of Motion Inertia?

Answer 21

an
object at rest will remain at rest and an
object moving at a constant velocity will
continue moving at a constant velocity,
unless it is acted upon by an unbalanced
force. Gravity and friction are unbalanced
forces.

Question 21

What is Inertia?

Answer 21

is the tendency of an object to resist a
change in motion.

Question 22

What is the factor of Inertia?

Answer 22

mass
greater mass ~ greater inertia ~ greater force to change motion

Question 23

What is Newton’s 2nd Law of Motion?

Answer 23

acceleration
depends on the object’s mass and the force
acting on the object.

Question 24

What is Newton’s 3rd Law of Motion Action/Reaction?

Answer 24

for every
action there is an equal but opposite reaction.

Question 25

What is newton’s cradle?

Answer 25

“For Every Action There Is An Equal But Opposite Reaction”

Question 25

What is Momentum?

Answer 25

a measure (quantity) of motion
more momentum ~ harder to stop

Question 26

What does the law of Conservation of Momentum state?

Answer 26

in the absence of outside forces, the total momentum of objects that interact does not change. The amount of momentum is the same before and after they interact.

Question 27

What happens in Collisions with Two Moving Objects?

Answer 27

Total momentum is
conserved. The momentum of one train car decreases
while the momentum of the other car increases.

Question 28

what happens in Collisions with One Moving Object?

Answer 28

Total momentum is
conserved. All of the momentum has been transferred from
the moving car to the initially stationary car.

Question 29

what happens in Collisions with Connected Objects?

Answer 29

Since the mass is
doubled and the velocity is divided in half, the total
momentum remains the same.