140-TJR-A10-2009-ANS

# 140-TJR-A10-2009-ANS - U N I V E R S I T Y OF W I N D S O R...

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U N I V E R S I T Y OF W I N D S O R DEPARTMENT OF PHYSICS Physics 64-140 Assignment No. 10 Name: Assigned: Wednesday, November 25 th , 2009 I.D.#: Due: MONDAY, November 30 th , 2009 1). Page 233 -36 The figure shows an overhead view of a 300 g ball with a speed v of 6.0 ms -1 strikes a wall at an angle θ of 30º and then rebounds with the same speed and angle. It is contact with the wall for 10 ms. In unit vector notation, what are (a) the impulse on the ball from the wall and (b) the average force on the wall from the ball? In the figure + y corresponds to the direction of the rebound (directly away from the wall) and + x towards the right. Using unit-vector notation, the ball’s initial and final velocities are: ˆˆ ˆ cos i sin j 5.2 i 3.0 j ˆ cos i sin j 5.2 i 3.0 j i f vv v v θθ =−= =+ = + G G ˆ ˆ respectively (with SI units understood). (a) With m = 0.30 kg, the impulse-momentum theorem yields ( ) 2 0.30 kg (3.0 m/s j) (1.8 N s)j fi Jm v m v =− = = G GG (b) The force on the ball by the wall is ˆ (1.8 0.010)j (180 N) j. Jt Δ= = G ˆ By Newton’s third law, the force on the wall by the ball is (that is, its magnitude is 180 N and its direction is directly into the wall, or “down” in the view given in the figure).

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## This note was uploaded on 03/15/2010 for the course RRF r103-09 taught by Professor Macdonal during the Spring '10 term at American University in Cairo.

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140-TJR-A10-2009-ANS - U N I V E R S I T Y OF W I N D S O R...

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