Projectile Motion

Question 1

What is projectile motion?

Answer 1

Objects in motion & affected by gravity
- called “trajectory” and represented by a parabolaaaright?? -J

Question 2

Tell me what you know about multi-Image Diagram 0-0

Answer 2

Vertical & Horizontal components

waiiit i thought multi image diagram is the pic with balls n vectors??-J

• i thought they were moving objects at different points in time…and how we can like do momentum and all that..-Y

Question 3

What are the things you have to remember about vertical & horizontal components?

Answer 3

• Vertical component: affected by m (gravity)
• Horizontal component: remain CONSTANT!

Question 4

Components questions require right triangles sometimes, list out the rules to find sides of a triangle?

Answer 4

Sin0= O/H (Opposite side)
Cos0= A/H (ADJ)
Tan0= O/A (Hyp)

Question 5

Small reminder!

Answer 5

Air resistance is ignored when calculating!! Thats why horizontal component is constant 0-0

Question 6

How to explain an object’s components when its launched into the air?

Answer 6

1. The horizontal component of… will always remain constant at…
2. • No external force acting on.. in the horizontal direction during…,
   • Resulting in NO a-> & NO change in speed (Newton’s 1st law: Inertia)
3. Vertical component of… will change
4. Force due to gravity is always acting on…
5. No other force to counteract gravity while…
6. F=ma-> implies there’s vertical component of…, speed is always changing (9.8ms-2 vertically downward)

Question 7

What is the best launched angle?

Answer 7

• ∠45*

Question 8

Why ∠45* is the best launched angle?

Answer 8

It provides a maximum range (distance) for projectiles that land at the same height they were launched.

Question 9

How does ∠45* relate to horizontal and vertical components?

Answer 9

• Vertical component of v increases = an increase in time of flight
  (Thus, the object can last longer in the air, travelling larger)

Question 10

What’s the role of AIR resistance?

Answer 10

It opposes the motion of the object through a medium, leading to a change in motion.

Question 11

Is air resistance a force?

Answer 11

Yes

Question 12

How is friction same and different from air resistance?

Answer 12

SAME: prevents objects from rolling/ moving

DIFFERENT: only apply for solid objects (on the ground)

the different part is for friction right?? ^^ - J

Question 13

When does drag force occur?

Answer 13

When objects change motion due to any medium (E.g. AirResistance, Water, etc)

Question 14

How does drag force work?

Answer 14

at in the opposite direction to object’s motion (affecting speed + direction)

Question 15

What are the factors that influence the magnitude of drag force?

Answer 15

• Speed of object
• Cross-sectional area
• Density of the medium (E.g. air particles contact with the object)

Question 16

What is drag coefficients (A type of friction)?

Answer 16

Variety of shapes that support the idea of “Aerodynamic” in cars and aircrafts.

guys 0-0 do we actually need to know this though? -Y

Question 17

What does drag coefficients do to drag force?

Answer 17

Decreases the drag force. 0-0

wait i thought SOME shapes would also help to increase it??? -Y

Question 18

Hence, do you think faster moving subject have more OR less friction?

Answer 18

More 0-0

Why? Cos when it travels faster, more air particles will make contact with it and causes lots of friction (drag force)!

Question 19

When does terminal velocity occur?

Answer 19

It occurs when drag force is on a moving body (balance force), results in 0 net force.

Question 20

So, what can we conclude from terminal velocity in terms of force and drag force?

Answer 20

force is EQUAL and OPPOSITE to drag force, making a balanced force.