Ap physics semester 1 ( unit 1 - 3) review

All of these are predictions

 What force causes centripetal motion for a car on a flat (unbanked) curve?

The force providing centripetal motion for a car on a flat (unbanked) curve is static friction between the tires and the road surface.

Max speed on a curve ( unbanked) without skidding ?

square root of (g* r* coefficient of static friction)

mass does not determine if the car skids. all that determines it is radius and and coefficient of friction

On a frictionless banked curve, what provides the centripetal force? 

normal force * sinθ

Equation for frictionless banked curve?

normal force = mg* cosθ

fc=(Fn)*cosθ

v=square root of ( r*g*tan θ)

Conceptual question for frictionless banked curve?

If you speed up, in what direction will you head ? You will go up the rampIf you speed up, in which direction will you head? You will go up the ramp.

If you slow down, in which direction will you head? You will go down the ramp.

If you speed up on a frictional banked curve, in which direction is friction pointing? Down the ramp.

If you slow down on a frictional banked curve, in which direction is friction pointing? Up the ramp.

Horizontal string question?

velocity = 2πR​/T tension = Mv²/r

• speed increases but radius remains the same - tension will increase (vice versa

• radius increase but spead remains the same - tension will decrease ( vise versa)

Vertical swinging block (algebraic equations )

1. At the top of the circular motion, tension, mg, and fc all point down, so you set the equations  (Fn + Mg = Mv² / r )

2. At the bottom of the circular motion, tension and Mv²/r points up, but mg points down, so you set the equation ( T - mg = Mv²/r)

Vertical swinging block ( conceptual questions )

• At which point is tension the greatest? the bottom

• At which point is tension the smallest? At the top ,

• minimum speed at the top to keep swinging? square root of g*r

Mass On Table + String Through A Hole

M₁ = mass hanging; M₂ = mass moving in circular motion on a table

. Find the tension? M₁*g = M₂*v²/r

• . You can also you that equation to find: radius, masses, and velocity

• it is the only equation to memorize in these scenarios, and most of the time it is in equilibrium

Conical Pendulum ( Algebraic equations )

• radius = length sinθ  velocity = squarer root of ( R*G*tan θ )

• tension = Mg/cosθ  centripetal force = mg*tan θ = mv²/r

• 2πr/( velocity )

Conical Pendulum ( conceptual question)

• Horizontal component of tension = centripetal force

• Vertical component of tension balances weight

• Centripetal force is not a separate force

• Mass often cancels in calculations

• Increasing θ → increases radius, speed, tension

• Period increases with radius

• Tension always points along the string

2 vehicles crash with different masses, what force do they exert on each other? 

Will always be equal. but for frq explanation “ newtons third law” as there mass are different but so are their accelerations due to that. so when they crash their force will be the same. 

Maximum static friction on an incline

θmax ​= tan^-1 (μs​)

If you push the bottom box and there’s another box on top, what is the same?

• Both boxes will have the same acceleration but different forces

• To calculate the maximum acceleration, the top box can experience before sliding, the equation is: μ_s​g

1 D motion equations

1 D motion Uniform motion position over time 

• slope if 0: the person is not moving

• slope is positive: they are moving, positive velocity, and 0 acceleration,

• slope is negative: they are moving, negative velocity, and 0 acceleration

• Position vs. Time graph: Curvature indicates changing slope → velocity is changing → acceleration ≠ 0.

• Direction of acceleration: If the curve is concave up → acceleration is positive; if concave down → acceleration is negative.