 #1
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 6
Homework Statement:

Jane drives her sportscar East along the road at a speed of 34 mph. Each tire has an inner radius of 0.4 m, an outer radius of 0.52 m, and a mass of 6 kg.
Jane sees a sign for an elementary school, so she gradually slows down to 19 mph over a period of 5 seconds, decelerating at a constant rate.
What was the torque applied to that tire during the period of acceleration? Provide both a magnitude and direction.
Relevant Equations:
 I=(1/2)(M)(radius1^2 + radius2^2)
I=(1/2)(6kg)(0.4^2 + 0.52^2) = 1.29 kg*m^2
initial:
34 mph= 15.2m/s
15.2m/s = (ω) (0.52m)
ω= 29.2 rad/s
after:
19 mph = 8.5m/s
8.5m/s = ω(0.52m)
ω= 16.3 rad/s
acceleration = (16.3 rad/s  29.2 rad/s) / 5s= 2.58 rad/s^2
torque= 2.58 rad/s^2 (1.29 kg*m^2 ) = 3.3 N*m
I am confused on what the direction of the torque is.
initial:
34 mph= 15.2m/s
15.2m/s = (ω) (0.52m)
ω= 29.2 rad/s
after:
19 mph = 8.5m/s
8.5m/s = ω(0.52m)
ω= 16.3 rad/s
acceleration = (16.3 rad/s  29.2 rad/s) / 5s= 2.58 rad/s^2
torque= 2.58 rad/s^2 (1.29 kg*m^2 ) = 3.3 N*m
I am confused on what the direction of the torque is.