In the figure above, the coefficient of static friction is 0.5. If the tension in the string is T, the acceleration of the system in motion is
-
A.
5 ms-2 -
B.
15 ms-2 -
C.
3 ms-2 -
D.
9 ms-2
Correct Answer: Option A
Explanation
Normal reaction R = 3 kg x 10 = 30N
coefficient of friction , μ = 0.5
∴ acting frictional force = μR = 30 x 0.5
Pulling/sliding force F = 6kg x 10 = 60N.
∴ Net downward force = ma = 60 – 15.0
=> (3 + 6)a = 45
∴ 9a = 45
a = 5m/s2