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1)The angular position of a point on the rim of a rotating wheel is given by = 5

ID: 1453116 • Letter: 1

Question

1)The angular position of a point on the rim of a rotating wheel is given by = 5.5 t + (-5.0)t2 + +(1.7)t3, where is in radians if t is given in seconds. What is the angular velocity at t = 2.0 s? Submit Answer Tries 0/8

What is the angular velociy at t = 4.0 s? Submit Answer Tries 0/8

What is the average angular acceleration for the time interval that begins at t = 2.0 s and ends at t = 4.0 s? Submit Answer Tries 0/8

What is the instantaneous angular acceleration at the beginning of this time interval? Submit Answer Tries 0/8

What are the instantaneous angular accelerations at the end of this time interval?

Explanation / Answer

given

= 5.5 t + (-5.0)t2 + +(1.7)t3

the angular velocity at t = 2.0 s

w 1= d /dt = d/dt (5.5 t + (-5.0)t2 + +(1.7)t3)

= 5.5-10t+5.14 t^2

=5.5-10(2) +5.14(2)^2

=6.06 rad/s

at t= 4.0 s

w2= 5.5-10t+5.14 t^2

=5.5-10(4) +5.14(4)^2

=47.74 rad/s

(c)

the average angular acceleration for the time interval that begins at t = 2.0 s and ends at t = 4.0 s

alpha = w2- w1/ t2- t1 = 47.74 -6.06/4-2 =20.84 rad/s^2

(d)

the instantaneous angular acceleration at the beginning of this time interval

alpha = d^2/dt^2 =-10+10.28 t

t = 2 s

alpha = -10+ 10.28 (2) = 10.56 rad/s^2

t = 4 s

alpha = -10+ 10.28 (4) = 31.12 rad/s^2