(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Five balls move through the air. All five have the same size and shape. Air resistance is not negligible. Rank in order, from largest to smallest, the magnitudes of the accelerations a1 to a5. Some may be equal. Give your answer in the form 1>2=3>4>5 and explain your ranking.

where Vy= velocity in the y-direction

A1: 50 g, just released, Vy=0

A2: 100 g, just released, Vy=0

A3: 50 g, Vy= -20 m/s

A4: 100 g, Vy= -20 m/s

A5: 50 g, Vy= 20 m/s

2. Relevant equations

1)

where D= drag,

A= cross-section area (which in this question is EQUAL for every ball),

v= velocty

vector D = ((1/4)Av^2, direction opposite the motion)

2)

where (Fnet)y= net force in the y direction,

m= mass

Acceleration going up: a= (Fnet)y/m

a= (-mg - D)/m

a= -(g + (D/m))

The magnitude of acceleration going up, which is the ball's deceleration as it rises, is (g + (D/m)).

As the ball falls, its acceleration going down is:

a= (Fnet)y/m

a= (-mg + D)/m

a= -(g - (D/m))

The magnitude of the acceleration going down is (g - (D/m))

3. The attempt at a solution

5>1=2>4>3

AM I CORRECT? PLEASE HELP. thank-you!

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# Homework Help: Physics ball thrown in air question

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