Question

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

Answer 1

-16t^2 + Vt = 98

-16t^2 + Vt -98 = 0

Answer 2

hmmmm

Answer 3

is that one of the answers?

Answer 4

this is a study group right?

Answer 5

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

Answer 6

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

Answer 7

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

Answer 8

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

Answer 9

-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

Answer 10

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

the wolf simplifies nicely :)

Answer 11

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

Answer 12

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

Answer 13

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

Answer 14

the 56th square root of 2?

Answer 15

no, 56 times the sqrt(2)

Answer 16

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

Answer 17

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

Answer 18

wow a was right thank you so much

Answer 19

yay!! lol

Answer 20

haha thanks so much

Answer 21

can you solve it for 105 feet by any chance?