Question

the distance d through which a stone falls from rest is proportional to the square of the time taken t. if the stone falls 45m in 3 seconds,how far will it fall in 6 seconds? how long will it take to fall 20m?

Answer 1

d=kt^2
45=9k,k=5
D=5(36)=180m
20=5t^2
4=t^2
t=2seconds.

Answer 2

ok @sarah_98

Answer 3

whats ^?

Answer 4

proportional?

Answer 5

ok any other method

Answer 6

plz wait

Answer 7

ok

Answer 8

s = ut + (1/2)(at^2); u = 0 as stone is dropped from rest.

Therefore, s = (1/2)(9.81)(6)^2, acceleration due to gravity is 9.81.

--> s = (4.905)(36) = 176.58m = 177m to 3 s.f. -----> answer 1

let s = 20 --> 20 = (4.905)(t)^2

--> (t)^2 = (20)/(4.905) = 4.077

--> t = square root of (4.077) --> t = 2.019 sec = 2.02 sec to 3 s.f. -----> answer 2

Answer 9

am i right @jiteshmeghwal9

Answer 10

yup!

u r always right dude :)

Answer 11

thanks

Answer 12

thnx... ok welcome

Answer 13

okay one question..

Answer 14

post it

Answer 15

whats ^