A block with an initial speed of 10 m/s slides on a horizontal surface and comes to rest after traveling a distance of 25 m. What is the coefficient of kinetic friction between the block and the surface? (Take g = 9.8 m/s\(^2\)).
A
0.1
B
0.3
C
0.2
D
0.5
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
Given: g = 9.8 m/s\(^2\), a = 10 m/s, v = 0( come to rest), s = 25m
v\(^2\) = u\(^2\) + 2as
- 100 = 2 x 25 x a
a = \(\frac{-100}{50}\) = - 2 deceleration is caused by kinetic friction
But, \(\mu\) = \(\frac{\text{f}}{\text{R}}\) = \(\frac{\text{ma}}{\text{mg}}\) = \(\frac{-2}{9.8}\) ≈ 0.2.
Source: WAEC / JAMB / NECO Classroom Archive (Record #75421)