cq_1_131

#$&*

PHY 201

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 **

Samantha Rogers

PHY 201

Seed 13.1

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? v0 = 20cm/s, `ds = 120 cm, a = 980cm/s^2 #$&*

• What therefore are its final velocity, displacement, change in velocity and average velocity in the vertical direction? vf = 485.39cm/s = sqrt((20cm/s)^2 +2(980cm/s^2)(120cm)), `ds = 120cm, `dv = 465.4cm/s = (485.39 - 20), vAve = 252.7cm/s = (485.39 + 20)/2. #$&*

• What are the ball's acceleration and initial velocity in the horizontal direction, and what is the change in clock time, during this interval? `dt = .47sec = 120cm/(252.7cm/s), v0 = 80cm/s, a = 0cm/s^2, #$&*

• What therefore are its displacement, final velocity, average velocity and change in velocity in the horizontal direction during this interval? `ds = 37.6cm = (80cm/s+80cm/s)/2 *.47s, vf = 80cm/s, vAve = 80cm/s, `dv = 0cm/s. #$&*

• After the instant of impact with the floor, can we expect that the ball will be uniformly accelerated?  the acceleration of the ball changes with time, and is no longer uniformly constant. #$&*

• Why does this analysis stop at the instant of impact with the floor? the analysis assumes uniform acceleration and acceleration isn't uniform any longer. #$&*

@&

Good.

However be sure you submit these documents in the appropriate format.

Instead of a response like

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? v0 = 20cm/s, `ds = 120 cm, a = 980cm/s^2 #$&*

you need to start your answer in the line after the question, and you need to leave the #$*& on its own line, as in the following:

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?

v0 = 20cm/s, `ds = 120 cm, a = 980cm/s^2 

#$&*

*@