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Mathematics
OpenStudy (anonymous):

A piece of chalk is tossed vertically upward by Prof. Schwarzenegger and hits the ceiling 98 feet above with a BANG. (Neglect the effects of air resistance. Round your answers to two decimal places.) (a) What is the minimum speed the piece of chalk must have been traveling to enable it to hit the ceiling? ft/s (b) Assuming that Prof. Schwarzenegger in fact tossed the piece of chalk up at 98 ft/s, how fast was it moving when it struck the ceiling? ft/s (c) Assuming that Prof. Schwarzenegger tossed the chalk up at 98 ft/s, and that it recoils from the ceiling with the same speed it had at the A piece of chalk is tossed vertically upward by Prof. Schwarzenegger and hits the ceiling 98 feet above with a BANG. (Neglect the effects of air resistance. Round your answers to two decimal places.) (a) What is the minimum speed the piece of chalk must have been traveling to enable it to hit the ceiling? ft/s (b) Assuming that Prof. Schwarzenegger in fact tossed the piece of chalk up at 98 ft/s, how fast was it moving when it struck the ceiling? ft/s (c) Assuming that Prof. Schwarzenegger tossed the chalk up at 98 ft/s, and that it recoils from the ceiling with the same speed it had at the

7 years ago
OpenStudy (amistre64):

-16t^2 + Vt = 98 -16t^2 + Vt -98 = 0

7 years ago
OpenStudy (amistre64):

hmmmm

7 years ago
OpenStudy (anonymous):

is that one of the answers?

7 years ago
OpenStudy (amistre64):

this is a study group right?

7 years ago
OpenStudy (amistre64):

its a thought i have as to what an answer might be, but i havent got to the end of the thought yet

7 years ago
OpenStudy (amistre64):

the derivative of that position formula tells us the speed, the velocity, at any given moment

7 years ago
OpenStudy (amistre64):

so when it is at 0 we know that is the least amount of velocity needed to hit the ceiling

7 years ago
OpenStudy (anonymous):

im sorry i just have no idea what to do for this problem any ideas help

7 years ago
OpenStudy (amistre64):

-16t^2 + Vt -98 = 0 -32t + V = 0 when t = V/32 .... so we could sub that back in to "t" to see if that helps out with the V

7 years ago
OpenStudy (amistre64):

http://www.wolframalpha.com/input/?i=simplify+-16%28V%2F32%29^2+%2B+V%28V%2F32%29+-98 the wolf simplifies nicely :)

7 years ago
OpenStudy (anonymous):

so which answer goes with a, b, and c? hahaha

7 years ago
OpenStudy (amistre64):

when we solve this for V we only got one good option: 56sqrt(2) i beleive

7 years ago
OpenStudy (amistre64):

I believe a is 56sqrt(2); but id have to dbl chk it with the wolf

7 years ago
OpenStudy (anonymous):

the 56th square root of 2?

7 years ago
OpenStudy (amistre64):

no, 56 times the sqrt(2)

7 years ago
OpenStudy (amistre64):

b and c are physics parts that i am not familiar with

7 years ago
OpenStudy (amistre64):

good luck with the rest of it, or if you have any questions about part a let me know

7 years ago
OpenStudy (anonymous):

wow a was right thank you so much

7 years ago
OpenStudy (amistre64):

yay!! lol

7 years ago
OpenStudy (anonymous):

haha thanks so much

7 years ago
OpenStudy (anonymous):

can you solve it for 105 feet by any chance?

7 years ago
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