Answer:
Coefficient of dynamic friction= md= 0.09931
Explanation:
To determine the coefficient of dynamic friction we must first match the friction force that is permendicular to the normal force of the block and opposite to the drag force, to the component of the drag force in this same direction. This component on the X axis of the drag force will be:
F= 90N × cos(30°) = 77.9423N
This component on the X axis of the drag force must be equal to the dynamic friction force that is equal to the coefficient of dynamic friction by the normal force of the block weight:
F= md × m × g= 77.9423N
m= mass of the block
md= coefficient of dynamic friction
g= gravity acceleration
F= md × 80kg× 9.81 (m/s²)= 77.9423(kg×m/s²)
md= (77.9423(kg×m/s²) / 784.8 (kg×m/s²)) = 0.09931