- #1
reverse
- 7
- 0
A magnetic computer disk 8.0 cm in diameter is initially at rest. A small dot is painted on the edge of the disk. The disk accelerates at 600 rad/ s^2 for 1/2 s, then coasts at a steady angular velocity for another 1/2 s . a) What is the speed of the dot at t = 1.0 s?
b)Through how many revolutions has it turned?
for a) i kept getting the answer wrong:
i did :
d=8.0cm
so r=4.0 cm
ti=0s
tf=0.5s
a=600 rad/s^2
vi=(2)(pi)(4.0cm) / 1.0s
so; vi=25m/s
and for part b)
i think you have to use the kinematic equation after you get vi.. I'm not sure tho.. am i right?? please help. thanks in advance!
b)Through how many revolutions has it turned?
for a) i kept getting the answer wrong:
i did :
d=8.0cm
so r=4.0 cm
ti=0s
tf=0.5s
a=600 rad/s^2
vi=(2)(pi)(4.0cm) / 1.0s
so; vi=25m/s
and for part b)
i think you have to use the kinematic equation after you get vi.. I'm not sure tho.. am i right?? please help. thanks in advance!