Question

a ball thrown vertically upwards from level ground is observed twice at a height H above the ground , within a time interval t the initial velocity of the ball was?

Answer 1

the ans=\[\sqrt{8gh +4g^2t^2}\]

Answer 2

http://books.google.co.in/books?id=jbidWQeq2WAC&pg=SA2-PA47&lpg=SA2-PA46&ots=3E5gOYToHa&dq=a+bullet+plunges+vertically+into+a+retarding+medium+with+an+initial+velocity+u.+its+velocity+is+reduced+by+20%25+in+a+distance+of+0.9m+in+the+medium+if+a+is+the+uniform+retardation+in+the+medium+then#v=onepage&q=a%20bullet%20plunges%20vertically%20into%20a%20retarding%20medium%20with%20an%20initial%20velocity%20u.%20its%20velocity%20is%20reduced%20by%2020%25%20in%20a%20distance%20of%200.9m%20in%20the%20medium%20if%20a%20is%20the%20uniform%20retardation%20in%20the%20medium%20then&f=false

Answer 3

plz view this website

Answer 4

@shameer1 have you realised that all the questions you posted recently are described by the same equation?

If 'up' is positive, the initial velocity u is positive too and acceleration is negative, because gravity act 'down'.

let z be displacement above ground where z=0, then:

z = -½gt² +ut

Solve for z=H, if H small enough, there should be 2 solutions.