48th to 52nd B.P.S.C. (Pre) 2008

A coin is tossed above the ground with a velocity of 9.8 m/s, then it will rise to the following height :

a9.8 m
b10 m
c4.9 m✓ Correct
d49 m

Explanation

Let, the velocity of coin at the height of h meter = 0 then ∵ $v^2 = u^2 - 2gh$ (where u = initial velocity and v = final velocity) $0 = (9.8)^2 - 2(9.8)h$ $h = \frac{(9.8)^2}{2 \times (9.8)} = \frac{9.8}{2}$ $= 4.9$ m

general-science