In: Physics
A projectile is launched at an angle of 30 degrees above the horizontal at a speed of 300 m/s. In what direction is it traveling after 3 s? In other words, what is the direction of its velocity vector? (Use |g| = 10 m/s2.)
vo = initial velocity = 300 m/s
= angle of launch =
30
Consider the motion along the vertical direction or Y-direction
Voy = initial velocity In Y-direction = vo
Sin = (300) Sin30 = 150
m/s
a = acceleration = - 10
t = time of travel = 3 sec
Vfy = final velocity after time "t" = ?
using the equation
Vfy = Voy + at
Vfy = 150 + (- 10) (3)
Vfy = 120 m/s
Consider the motion along the horizontal direction or X-direction
Vox = initial velocity In X-direction = vo
Cos = (300) Cos30 = 259.8
m/s
a = acceleration = 0
t = time of travel = 3 sec
Vfx = final velocity after time "t" = ?
using the equation
Vfx = Vox + at
Vfx = 259.8 + (0) (3)
Vfx = 259.8 m/s
= angle after time
"t"
=
tan-1(Vfy /Vfx ) =
tan-1(120/259.8 ) = 24.8 deg