Question

how to calculate the tie when the initial velocity of and object (rock) is given ( 12m/s 42 degrees above the horizontal. The object land at the other side of say a moat at a level of 9.5 m below the initial level. Air resistance is negligible. What is the time of flight? (the answer given in the book is 2.4s) How do you get that answer, what formulas do you use?

Answer 1

what is "tie"?

Answer 2

u = 12 cos 42 = 8.92 m/s the whole time

Vi = 12 sin 42 = 8.03
v = Vi - 9.81 t

h = 9.5 + Vi t - 4.9 t^2
0 = 9.5 + 8.03 t - 4.9 t^2

t = [ -8.03 +/- sqrt (8.03^2-4*-4.9*9.5)]/-9.81

t = [-8.03+/-sqrt(251) ]/-9.81

t = 2.43 s

Answer 3

bruh rearranged the 0=9.5+8.035-4.9t^2 so people know what you are doing

Answer 4

8.03t^^