Practice Problems for 1st Semester Exam
Practice Problems for 1st Semester Exam
Practice Problems for 1st Semester Exam
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14. Brian’s favorite ride at Busch Gardens is the rotor, which has a radius of 4 m.<br />
The ride takes 2 seconds to make one full revolution. Brian’s mass is 60 kg.<br />
r = 4m m = 60kg T = 3s<br />
a. What is Brian’s frequency?<br />
f = 1/T f = 1/ 3s f = .33 Hz<br />
b. What is the period of Brian’s circular motion?<br />
T = 3 s<br />
c. What is Brian’s rotational velocity?<br />
rotational velocity = frequency rotational velocity = .33 turns per second = .33Hz<br />
d. What is Brian’s tangential velocity.<br />
v = 2π r / T v = 2 (3.14)( 4m) / 3s v = 8.37 m/s<br />
e. What is Brian’s centripetal acceleration?<br />
ac = v 2 /r ac = (8.37 m/s) 2 / 4m ac = (70.0569 m 2 /s 2 ) / 4m ac = 17.51 m/s 2<br />
f. What is the centripetal <strong>for</strong>ce that is exerted on Brian to maintain his circular motion?<br />
Fc = mac Fc = (60kg) ( 17.51 m/s 2 ) F = 1050.60 N<br />
15. Cody twirls a round piece of pizza dough overhead. It revolves .25 times in one second.<br />
A 0.02 kg piece of pepperoni is stuck on the dough 0.13 m from the pizza’s center.<br />
f = .25 Hz m = .02 kg r = .13 m<br />
a.) What is the frequency of the pepperoni?<br />
f = .25 Hz<br />
b.) What is the pepperoni’s period?<br />
T = 1/f T = 1/.25Hz T = 4s<br />
c.) What is the pepperoni’s tangential speed?<br />
v = 2π r / T v = 2 (3.14)( .13m) / 4s v = .20 m/s<br />
d.) What is the pepperoni’s centripetal acceleration?<br />
ac = v 2 /r ac = (.20 m/s) 2 / .13m ac = (.04 m 2 /s 2 ) / .13m ac = .31 m/s 2<br />
e.) What is the centripetal <strong>for</strong>ce on the pepperoni?<br />
Fc = mac Fc = (.02 kg) (.31m/s 2 ) F = .006 N
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