Physics 1 Flashcards
- Name 5 scalars
- “MaTe Speed TiDe”
- Mass
- Temp
- Speed
- Time
- Density
- Name 8 vectors
- “VeDiAcFo MagMoImTo”
- Velocity
- Displacement
- Accel
- Force
- Mag. Field
- Momentum
- Impulse
- Torque
Think of force as…
- any influence capable of:
- causing a mass to accelerate
Center of Mass equation
- What should you remember to keep in mind with these problems?
Cmass=(r1m1+r2m2….)/mtotal
- r=reference point
Hint: choose a reference point from which to measure each displacement vector
- Constant net force causes WHAT acceleration?
- and therefore WHAT velocity?
-
CONSTANT acceleration
- therefore CHANGING velocity!!!
- When you see “constant velocity” or “constant speed,” think? (5)**
- NO acceleration
- NO net force (Fnet=0)
- All forces sum to zero
- up forces=down forces, left=right, etc.
- NO change in direction
- The object is in EQUILIBRIUM!!!
- When you see a LINEAR MOTION GRAPH, you’ll ask yourself these 6 things:
- What does the SLOPE represent?
- Is this slope (+) or (-)?
- It the slope….
- Constant (straight line) or
- Non-constant (curved line)?
- What is the value on the x-axis?
- Is the y value (+) or (-)
- aka are you above or below the x-axis?
- At t=0, do I expect the value on the y-axis to be:
- LARGE, or
- SMALL?
- When I see the word “projectiles,” I will remember 7 things:
- Horizontal VELOCITY:
- never changes
- Horizontal ACCELERATION:
- is always =0
-
VERTICAL acceleration:
- is always 10 m/s2 downward
- Vertical BEHAVIOR
- is always symmetrical
- ex: upward trip=downward trip
- is always symmetrical
-
Time in air (Tair) depends on:
- VERTICAL COMPONENT of velocity ONLY!!
- Range depends on both:
- vertical AND horizontal components
- Time is always the same for both x and y components of the motion
Law of Universal Gravitation formula
Fg=Gm1m2/r2
- Fg=Gm1m2/r2
- gives WHAT?
- the force DUE to gravity
- NOT gravity itself!
- Formula for GRAVITY (ITSELF!)
- aka “acceleration due to gravity”
- aka “strength of gravitational field”
g=Gm/r2
- What are the 2 physics equations that could be used FOR FALLING OBJECTS?
- x=½at2
- V=√2gh
Time in air equation
-
Tair=?
- this equation can ONLY be used to calculate what?
Tair=2V/g
- can only be used to calculate “round trip” times
- aka total time in air,V, must be vertical component of INITIAL velocity
- At terminal velocity…
- What 2 things are happening?
- Give the formula for terminal velocity
- object has stopped accelerating
- forces of gravity and air resistance are BALANCED
Fair=mg
Vavg=?
Vavg=(V1+V2)/2
- For PEgrav, which variation will you MOST LIKELY see on the MCAT?
PEgrav=mgh
- (At or near earth’s surface; g=10m/s2)
Inclined Planes
- When is the equation when solving for:
Force down an IP PARALLEL to the surface?
F=mgsinθ

Inclined Planes
When is the equation when solving for:
Normal Force (F<strong>N</strong>) down an IP
FN=mgcosθ

Inclined Planes
- When is the equation when solving for:
Velocity of a particle at the base of an inclined plane
- What other kind of problem could this equation be used to help solve?
Vfinal = √2gh

Can also be used to help solve for
FALLING OBJECT problems
Inclined Planes
- When is the equation when solving for:
ACCELERATION DOWN an IP
- What other equation can you derive this from?
HINT:
- Notice you’re solving for acceleration DOWN an IP.
- What other equation solves for something DOWN an IP that you know of?
a=gsinθ
Derived from:
- F=mgsinθ (Force DOWN an IP)
F=ma, ∴ “a”=gsinθ

Inclined Planes
- Why does Vf = √2gh work for either falling bodies OR a mass on an inclined plane?
HINT:
What is the above equation derived from?
What is happening to an object as it goes from the point where it is dropped until hitting the ground?
The formula Vf = √2gh is derived from CONSERVATION OF ENERGY
- by equating mgh to ½mv2
- and solving for “v”
As long as friction, air resistance, etc. are ignored (which they are), energy will be conserved in an identical way…
WHETHER THE OBJECT FALLS DIRECTLY TO THE GROUND OR ROLLS DOWN A PLANE

Inclined Planes
As the angle of incline of a plane INCREASES:
- What happens to the value of a?
- What happens to the value of sinθ and cosθ?
- What happens to the normal force?
- What happens to the force down the plane?
- What is the maximum value for acceleration down an inclined plane?
- What is the minimum value for acceleration down an inclined plane?

- ) Because the acceleration down a plane is directly related to the SINE of the angle
* (F=mgsinθ, where gsinθ=”a,” since F=ma)*
- the greater the angle, the closer the sine of the angle will be to ONE (1.0)
- Because increasing the angle of SIN:
- 0 ⇒ 1.0
- Therefore, the larger the angle, the closer the acceleration will be to 9.8m/s2*
2. ) The normal force is related to the cosine of the angle (Fn=mgcosθ…OSD) , so as the angle increases, this value gets closer to zero - Because increasing the angle of COS:
- 1.0 ⇒ 0
- Therefore, as the angle increases the normal force decreases
- ) The force down an inclined plane is also related to the sine of the angle
* so it too will increase as the angle of incline increases - ) The theoretical maximum incline is 90 degrees
* where acceleration would be exactly 9.8 m/s2 - ) The minimum would be a plane with NO angle of incline
* where acceleration down the plane would be ZERO

Tension Forces
What is the tension in a rope being pulled from opposite ends with identical forces of 50N?
50N
Tension Forces
- A 500kg elevator is being accelerated upward by a cable with a tension of 6,000N
What force does the elevator exert on the cable?
TRICK QUESTION!
According to Newton’s 3rd Law, if the elevator CABLE is pulling on the ELEVATOR with 6,000N of force…
…then the ELEVATOR must be pulling on the
CABLE with a force of 6,000N






