a) The formula to calculate the required oil flow rate isQ= A × VWhere Q is the flow rate, A is the cross-sectional area, and V is the velocity. In this problem, the bore diameter is given as 5 cm, which means that the radius, r = 2.5 cm = 0.025 m. Therefore, the cross-sectional area of the hydraulic cylinder is A = πr².Q = A × V= π × 0.025² × 0.5= 0.00098 m³/sb) The formula to calculate the required hydraulic pressure isP= F / Awhere P is the pressure, F is the force, and A is the area. In this problem, the maximum load that the digger can lift vertically is given as 800 kg, which means that the force, F = 800 × 9.81 = 7848 N. Therefore, the area, A = πr² = π × 0.025² = 0.00196 m².P = F / A= 7848 / 0.00196= 4 × 10⁶ Pa (4 MPa)c) The hydraulic power is given by the formulaP = Q × P = 0.00098 × 4 × 10⁶= 3920 WThe electrical power of the electric motor driving the pump is given by the formulaP = η × PeWhere η is the efficiency of the pump, and Pe is the electrical power input to the motor. In this problem, the efficiency of the pump is given as 85%. Therefore,P = 0.85 × Pe=> Pe = P / 0.85= 4600 W (approximately)d) If the digger is used to pull rather than lift, it would not be able to develop the same equivalent load of 800 kg because when the digger is lifting, it is working against gravity, which provides a constant opposing force. However, when the digger is pulling, the opposing force is friction, which is not a constant and can vary depending on the surface conditions. Therefore, the digger may not be able to develop the same equivalent load of 800 kg when pulling.