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Phy 121
Your 'cq_1_13.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** CQ_1_13.1_labelMessages **
A ball rolls off the end of an incline with a vertical velocity of 20 cm/s downward, and a horizontal velocity of 80 cm/s. The ball falls freely to the floor 120 cm below.
• For the interval between the end of the ramp and the floor, hat are the ball's initial velocity, displacement and acceleration in the vertical direction?
⁃ a= 980 cm/s^2 v0= 20 cm/s 'ds=120cm
⁃ Vf^2=v0^2+2 a ‘ds
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⁃ Vf^2= 20cm/s^2+2(980cm/s^2)(120cm)
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⁃ Vf= sqrt 235,600
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⁃ Vf= 485 cm/s
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⁃ vAve= (485cm/s+20cm/s)/2= 252 m/s
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⁃ vAve= ‘ds/’dt
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⁃ 252m/s= 120cm/s/’dt
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⁃ .48s= ‘dt#$&*
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• What therefore are its final velocity, displacement, change in velocity and average velocity in the vertical direction?
• v0=80 cm/s 'dt=.48 s
⁃ 'ds=vAve*'dt
⁃ 80 cm/s*0.48 s= 48.4 cm #$&*
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This is the correct analysis of the horizontal motion.
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• What are the ball's acceleration and initial velocity in the horizontal direction, and what is the change in clock time, during this interval?
⁃ v0 = 80cm/s, 485 cm/s-20cm/s= 465 cm/s a= 980 cm/s^2 (due to gravity)
⁃ 'dt=465cm/s / 980cm/s^2= 0.474seconds
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Very good.
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