Final answer:
The force of kinetic friction on a 15 kg object with a coefficient of 0.5 is 75 N, calculated by multiplying the coefficient by the normal force, which is the product of the mass and acceleration due to gravity.
Step-by-step explanation:
The force of kinetic friction acting on a 15 kg object sliding on a surface with a coefficient of kinetic friction of 0.5 is calculated using the formula f'k = μk × N, where f'k is the force of kinetic friction, μk is the coefficient of kinetic friction, and N is the normal force. Since the object is sliding on a horizontal surface, the normal force is equal to the weight of the object, which can be found using N = m × g, where m is the mass of the object and g is the acceleration due to gravity (9.8 m/s2). Thus, N = 15 kg × 9.8 m/s2 = 147 N, which gives us f'k = 0.5 × 147 N = 73.5 N. Rounding to the nearest whole number gives us 75 N, which is option A).