Object A (in free fall) hits object B (ascending with constant velocity)

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The discussion revolves around solving a physics problem where object A falls from a height of 2 meters while object B ascends with a constant velocity. The participants emphasize the importance of defining a coordinate system and correctly applying kinematic equations to find the time of impact. They suggest using the quadratic formula to solve the resulting equation, which involves the distances and velocities of both objects. There are corrections made regarding the units of velocity and the setup of the equations to ensure they reflect the correct physical scenario. Ultimately, the conversation highlights the need for clarity in mathematical representation and problem-solving techniques.
  • #31
groetschel said:
Ok, let me try this...
##h - vt - \frac 1 2 g t^2 = 0##
$$ ax^2 + bx + c = 0 $$
What's your final answer for t?
 
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  • #32
groetschel said:
???
Please try it on your own:
H = 2m
v = 5.833 m/s
g = 9.8 m/s2

Solve the equation for t...
You could always have checked this on a spreadsheet. You want to find ##t## such that:
$$5.833t + \frac 1 2 9.8 t^2 = 2$$You could start at ##t = 0.01## and go up in increments of ##0.01## until you get to ##2##:

ug
5.833​
9.8​
tut1/2 gt^2d
0.01​
0.05833​
0.00049​
0.05882​
0.02​
0.11666​
0.00196​
0.11862​
0.03​
0.17499​
0.00441​
0.1794​
0.04​
0.23332​
0.00784​
0.24116​
0.05​
0.29165​
0.01225​
0.3039​
 
  • #34
groetschel said:
Ok, let me try this...
##h - vt - \frac 1 2 g t^2 = 0##
$$ ax^2 + bx + c = 0 $$
Put the first into the form of the second and identify what is a,b and c. Then use the formula given earlier for the quadratic in terms of a,b,c to solve for t (or x if that's easier).
 

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