5. A helicopter travelling horizontally at 150 km/h[E] executes a gradual turn, and eventually is moving at 120 km/h[S]. If the turn takes 50 s to complete, what is the average acceleration of the helicopter? (3.8 km/h/s[$51*W]) 6. A hockey puck hits the boards with a velocity of 10 m/s at an angle of 20" to the boards. It is deflected with a velocity of 8.0 m/s at 24 to the boards. If the time of impact is 0.03 s, what is the average acceleration of the puck? (2.3 X 103 m/s' out from the boards at an angle of 107")