Soil borings completed for a subsurface investigation indicate the site is underlain by a deposit of sandy soils. At one boring location, the blow count logged for the standard penetration test, N 60...

Soil borings completed for a subsurface investigation indicate the site is underlain by a deposit of sandy soils. At one boring location, the blow count logged for the standard penetration test, N₆₀, while sampling at a depth of 7 m was 24 blows. The sand has a unit weight of 16.5 kN/m³. Using criteria that relates SPT results and the soil angle of internal friction, estimate the value of f for the sand at the sample depth.