Air in a 120-km/h wind strikes head-on the face of abuilding 45 m wide by 65 m high and is brought to rest. If airhas a mass of 1.3 kg per cubic meter, determine the averageforce of the wind on the building.

Lectures 1 2 and 3 Average Speed & Average Velocity vavgdistancetime=dt *speed is a scalar (magnitude with no direction vavgdisplacementtime= rt * velocity is a vector (has direction) → UNITS: ms vavg and r point in direction of motion vx= xf-x0t → xf=x0+t(vx) *with constant velocity Negative slope = negative velocity Steeper slope = faster speed Acceleration aavgvt *rate of change of velocity (slowing, speeding, changing direction) aavgv - n+1 n → UNITS: ms 2 → If v and a are point in the same direction, the object is speeding up afree fall0 ms2 → 1 dimensional acceleration down a slope: as= g(sin) Ki