Chapter 7

Question 1

What is the equation for radiant angle measure?

Answer 1

θ (in radians) = s/r
S=θr
Slide 23 oct 17

Question 2

What is the symbol and equation for angular speed?
Symbol and equation for angular acceleration?
What are the directions of rotation that are positive and negative?

Answer 2

ω
ωav= Δθ/Δt
Or ω=vt/r
α
αav= Δω/Δt

CCW- +
CW- -

Question 3

What is the equation for finding tangent velocity at a given time in an angular question and what is the instantaneous angular acceleration?

Answer 3

Vt=rω

at= rα

Question 4

What does centripetal mean?

Answer 4

Towards the centre

Centripetal acceleration is always facing in on a circular path

Question 5

What is the equation for centripetal acceleration?

Answer 5

Ac= rw^2= v^2/r

Question 6

If an object is moving in a circular path at a changing speed what is its acceleration?

Answer 6

Acceleration has both a tangential component (tangential acceleration due to angular component)
And a radial component (centripetal acceleration)
Atot=square root(at^2 + ac^2)

Question 7

Is there a net force causing a centripetal acceleration?

Answer 7

Yes makes it face towards the centre of circular path and causes a change in direction of velocity vector
If net force turns to zero the object will go straight tangent to the circle where the net force turned zero

Question 8

How does the value of potential energy or gravity change as the size of the radius changes?

Answer 8

PEgrav-> 0
As
r-> infinity

Question 9

What is escape speed?

Answer 9

Minimum initial speed that an object must be given in order for it to just escape the gravitational pull of another object