Division 4.5

The required impact velocity, the angle of impact and the impactor mass are determined in accordance with points 4.6. and 4.8.1. The tolerance on the impact velocity is ±2 % and the tolerance on the impact direction is ±2°. The effect of gravity is taken into account before the time of first contact. The impactor mass shall be measured to an accuracy of better than ±1 %, and if the measured value differs from the required value then the required velocity shall be adjusted to compensate, in accordance with point 4.8.1.