Step 1: Recall the formulas for linear speed and centripetal acceleration in uniform circular motion.
The linear speed (v) is related to the angular velocity (ω) and radius (r) by:
v=rω
The centripetal acceleration (ac) can be expressed in terms of linear speed and radius, or angular velocity and radius:
ac=rv2=rω2
Step 2: Define the initial conditions.
Let the initial angular velocity be ω1.
Let the initial linear speed be v1=V.
Let the initial radius be r1.
The initial centripetal acceleration is ac1.
From the formulas:
V=r1ω1(1)
ac1=r1ω12(2)
Step 3: Define the final conditions based on the problem statement.
The angular velocity is doubled: ω2=2ω1.
The centripetal acceleration is unchanged: ac2=ac1.
Let the new linear speed be v2.
Let the new radius be r2.
From the formulas:
v2=r2ω2=r2(2ω1)(3)
ac2=r2ω22=r2(2ω1)2=4r2ω12(4)
Step 4: Use the condition that centripetal acceleration is unchanged to find the relationship between the radii.
Since ac1=ac2:
r1ω12=4r2ω12
Divide both sides by ω12 (assuming ω1=0):
r1=4r2
This means the new radius is r2=4r1.
Step 5: Substitute the relationship for the radius into the equation for the new speed.
Substitute r2=4r1 into equation (3):
v2=(4r1)(2ω1)
v2=42r1ω1
v2=21(r1ω1)
Step 6: Substitute the initial speed V.
From equation (1), we know that V=r1ω1.
Substitute V into the expression for v2:
v2=21V
The new speed will be 2V.
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