a shell fired from a cannon at 60 ° from horizontal strikes a target 20m high at a distance 80m. Calculate the initial velocity

Respuesta :

consider the motion along the X-direction

X = horizontal displacement = 80 m

[tex]V_{ox}[/tex] = initial velocity along the x-direction = v Cos60

t = time of travel

using the equation

X = [tex]V_{ox}[/tex]   t

80 = (v Cos60) (t)

t = 160/v                                         eq-1


consider the motion in vertical direction :

Y = vertical displacement = 20 m

[tex]V_{oy}[/tex]  = initial velocity in Y-direction = v Sin60

a = acceleration = - 9.8 m/s²

t = time of travel = 160/v

using the equation

Y = [tex]V_{oy}[/tex]  t + (0.5) a t²

20 = (v Sin60) (160/v) + (0.5) (- 9.8) (160/v)²

v = 32.5 m/s