Rotational Collisions

Rotational Collisions ( supplements )

Procedure 1

Select “smart pully timer” --> “motion timer” --> “release the platter”--> “graph data”--> select “E – rotational apparatus“ -->“velocity vs. time”
The slope is “a ”, angular acceleration.

m : the total hanging mass
r : the radius of the middle step
g = 9.8 m/sec² or 980 cm/sec²
a : angular acceleration
I_total+ mr² = mgr / a

object	m	r	a	mgr	I_total+ mr²	I_total
Platter
Platter+Ring
Platter+bar
Platter+ Platter

I_Platter = _______________ , I_bar = _______________

I_ring = _______________ , I_AuxPlatter = _______________

Procedure 4

Print out a graph of “angular velocity vs. time”.
L_i = I_i w _i, I_i is the moment of inertia for moving object.
L_f = I_fw _f , I_f is the moment of inertia for moving and dropping object.
D L = L_f - L_i

Moving Object	Dropping Object	w _i rad/s	w _f rad/s	L_i kg-m²/s	L_f kg-m²/s	D L/L_i x 100%
Platter	Platter
Platter+ring	Platter
Platter+bar	Platter
platter	bar
2 platters	bar

D K = K_f - K_i

Moving Object	Dropping object	w _i rad/s	w _f rad/s	K_i joules	K_f joules	D K/ K_i x 100%
Platter	Platter
Platter+Ring	Platter
Platter+Bar	Platter
Platter	Bar
2 Platters	Bar

Answer the questions.