A force F required to keep a 5 kg mass moving round a cycle of radius 3.5 m at a speed of 7 ms-1. What is the speed, if the force is tripled?
-
A.
4.0 ms-1 -
B.
6.6 ms-1 -
C.
12.1 ms-1 -
D.
21.0 ms-1
Correct Answer: Option D
Explanation
The force which is centripetal
F = MV2_R
=5 x 723.5
= 70
Since, force is 70 N when speed is 7m/s
Hence 3 * 70N will equal 21 m/s
V = √(Fr) and if F is tripped, then