A machinist turns the power on to a grinding wheel, at rest, at time t = 0 s. Th

Question

A machinist turns the power on to a grinding wheel, at rest, at time t = 0 s. The wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 69 rad/s. The wheel is run at that angular velocity for 29 s and then power is shut off. The wheel slows down uniformly at 1.6 rad/s2 until the wheel stops. In this situation, the total number of revolutions made by the wheel is closest to: A machinist turns the power on to a grinding wheel, at rest, at time t = 0 s. The wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 69 rad/s. The wheel is run at that angular velocity for 29 s and then power is shut off. The wheel slows down uniformly at 1.6 rad/s2 until the wheel stops. In this situation, the total number of revolutions made by the wheel is closest to: 915 1220 305 610 1525

Explanation / Answer

f = o + t

= 6.9 rad/s^2

Angle turned in that time = 0.5t^2 = 0.5 * 6.9 * 100 = 345 radians

Then it moves for 29 s with that angular speed so angle turned again = 69 * 29 = 2001 rad

Now the wheel slows down at 1.6 rad/s^2

Hence

f^2 = o^2 + 2

= 69^2/(2 * 1.6) = 1487.81 radians

hence total angle swept in this much time = 3833.8125 radians

Number of revolutions made = 3833.8125/2 = 610 revolutions

Hecne option D is the correct answer.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.