The roller-coaster track shown is contained in a vertical plane. The portion of

Question

The roller-coaster track shown is contained in a vertical plane. The portion of track between A and B is straight and horizontal, while the portions to the left of A and to the right of B have radii of curvature as indicated. A car is traveling at a speed of 72 km/h when the brakes are suddenly applied, causing the wheels of the car to slide on the track (mu k = 0.20). Determine the initial deceleration of the car if the brakes are applied as the car (a) has almost leached A, (b) is traveling between A and B, (c) has just passed B. Fig. P12.45

Explanation / Answer

speed= 72 kmph = 20 m/s
a)
radial acc =v^2/r = 20^2/30 = 13.33
radial acc = g = 0.2 *10 = 2

total acc = (2^2 + 13.33 ^2) = 13.48

b)

radial acc = g = 0.2 *10 = 2

total acc = 2 m/s^2

c)

radial acc =v^2/r = 20^2/45 = 8.88
radial acc = g = 0.2 *10 = 2

total acc = (2^2 + 8.88^2) = 9.1 m/s^2

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

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