Answer:
2.57in
Explanation:
Let's assume the efficiency of the wheel and axle system is 100%
Efficiency = MA/VR ×100
100 = MA/VR × 100
MA/VR = 1
mechanical Advantage MA = Load/effort
MA = 70/12
MA = 5.83
Velocity ratio VR = Diameter of wheel/diameter of axle
VR = 15/d
Substitute into the formula the given data and get d
1 = (70/12)÷(15/d)
1 = 70/12×d/15
1 = 70d/180
Cross multiply
180 = 70d
d = 180/70
d = 18/7
d = 2.57in
Hence the maximum diameter of the axle is 2.57in