-
A particle of mass 10 g moves along a circle of radius 6.4 cm with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic energy of the particle becomes equal to 8 × 10–4 J by the end of the second revolution after the beginning of the motion ?
-
- 0.1 m/s2
- 0.15 m/s2
- 0.18 m/s2
- 0.2 m/s2
Correct Option: A
| Given : Mass of particle, M = 10g = | kg | |
| 1000 |
radius of circle R = 6.4 cm
Kinetic energy E of particle = 8 × 10–4J
acceleration at = ?
| mv2 = E ⇒ |  |  | v2 = 8 × 10–4 | |||||
| 2 | 2 | 1000 |
⇒ v2 = 16 × 10–2
⇒ v = 4 × 10–1 = 0.4 m / s
Now, using v2 = u2 + 2ats (s = 4πR)
| (0.4)2 = 02 + 2at | | 4 × | × | | ||
| 7 | 100 |
| ⇒ at = (0.4)2 × | = 0.1 m / s2 | |
| 8 × 22 × 6.4 |
