Post a New Question


posted by .

A student throws a set of keys vertically upward to her sorority sister, who is in a window 4.30 m above. The keys are caught 1.30 s later by the sister's outstretched hand.
(a) With what initial velocity were the keys thrown?
_____________ m/s upward

(b) What was the velocity of the keys just before they were caught?
___________ m/s upward or downward

Can someone help me set up ?Or explain it please. Thank you!

  • physics -

    (a) 4.30 = Vo*t - (g/2) t^2
    = Vo*1.3 - (1/2)*9.81*(1.3)^2
    Solve for Vo.
    1.3*Vo = 4.30 + 8.29 = 12.59 m
    Vo = 9.68 m/s

    (b) Use conservation of energy
    Initial KE - Final KE = M g * 4.30 m
    (Vo^2 - Vf^2)/2 = g * 4.30 m

    Solve for the final velocity Vf. The keys could be on the way up or down.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

More Related Questions

Post a New Question