= 66 kg x 2 m/s^2 = 132 N. Thus, a force of 132 N is needed to accelerate a skier, having a mass of 66 kg, by 2 m/s^2. Note that we can also use the same equation to determine the weight of the skier. In that case, the acceleration will be equal to the acceleration due to gravity (9.8 m/s^2).