In order to study effects of velocity and acceleration of a flow to the pressure on an obstacle, a small sphere with a pressure hole was placed in a periodically pulsating jet. Both the instantaneous pressure on the sphere and the instantaneous velocity of the flow field when the sphere was absent were measured. By using periodic sampling and averaging techniques, only periodic or deterministic component of the signal was recovered and any random component caused by turbulence suppressed. The measured surface pressure was expressed in terms of this measured velocity and acceleration of the flow. A simple inviscid theory was developed and the experimental results were compared with it.