Final answer:
The force of friction is 0.8474 N, equal to the pushing force. To find the coefficient of kinetic friction, divide the frictional force by the normal force, which is the weight of the block (mass times gravity).
Step-by-step explanation:
To find the force of friction acting on a block sliding on a surface at constant velocity, we can use the information provided about the pushing force and the weight of the block. The force required to maintain constant velocity equals the force of friction due to Newton's first law (body in equilibrium). Since a constant force of 0.8474 N is applied to the block to maintain constant speed, this is also the magnitude of the frictional force.
The coefficient of kinetic friction (μ) can be calculated using the equation: f_k = μ * N, where f_k is the kinetic frictional force and N is the normal force (equal to the weight of the block when on a horizontal surface). The weight of the block is calculated by its mass (0.400 kg) times the acceleration due to gravity (approx. 9.80 m/s²), resulting in a normal force of about 3.92 N. Using the frictional force of 0.8474 N, we can rearrange the equation to solve for μ: μ = f_k/N = 0.8474 N / 3.92 N.
Therefore, to maintain a constant speed on a wood surface, the coefficient of kinetic friction would be approximately the ratio of the frictional force to the normal force.