Question

A body is projected from the ground at an angle of 30° with the horizontal at an initial speed of 128
ft/s. Ignoring air friction, determine (a) in how many seconds it will strike the ground, (b) how high it
will go, and (c) what its range will be.​

Answer 1

Answer:

u = 128 ft/s, angle (x) = 30 degrees.

a) Time period = 2u sinx / g = 2*128*sin30 / 10 = 2*128*1/2 / 10 = 12.8 seconds.

b) Max. height = u^2 sin^2(x) / 2g = 128*128*sin^2(30) / 2*10

                                                       = 128*128*1/4 / 20 = 64*64/20 = 32*32/5

                                                                                                          = 204.8 ft.

c) Range = u^2 sin2x / g = 128*128*sin60 / 10 = 128*128*√3/20 = 219.2√3 ft.