Answer:
1.08 m/s^2
Explanation:
The maximum value of static friction F_s = μ_s mg
where μ_s = coefficient of static friction
m= mass of box= 50kg
g= 9.81 m/s^2 , acceleration due to gravity
F_s = 0.5×50×9.81 =245 N
Since, the applied force is greater than the maximum value of static friction F_s, the object must be in motion. Hence, kinetic friction must be taken into account and not static friction.
By equilibrium condition
ma = F - μ_k m g
where F = 250 N, μ_k = coefficient of kinetic friction = 0.4, m= 50 Kg
a = acceleration of the box
50a = 250-0.4×50×9.81
Solving we get a= 1.08 m/s^2
