A projectile is shot from the ground at an angle of pi/4 π4 and a speed of 6 m/s6ms. Factoring in both horizontal and vertical movement, what will the projectile's distance from the starting point be when it reaches its maximum height?

1 Answer
Apr 17, 2016

2.6m2.6m

Explanation:

Split up the velocity into its horizontal and vertical components using trigonometry,

V_h=6m/s*cos(pi/4)=6cos45Vh=6mscos(π4)=6cos45
V_v=6m/s*sin(pi/4)=6sin45Vv=6mssin(π4)=6sin45

Now you should work out the halfway point, where upwards velocity becomes 00 and the projectile reaches its maximum point

v=u+atv=u+at
0=V_v+"gt"0=Vv+gt,

where the acceleration of gravity g=-9.8g=9.8

0=6sin45-9.8t0=6sin459.8t

t=(6sin45)/9.8t=6sin459.8
t=0.433st=0.433s

Now you can work out the horizontal distance by

s=vts=vt
s=V_h*0.433s=Vh0.433
=6cos45*0.433=1.84m=6cos450.433=1.84m

and the vertical distance by

s=V_v*0.433s=Vv0.433
=6sin45*0.433=1.84m=6sin450.433=1.84m.

The overall distance is found by Pythagoras' theorem,

c=sqrt(a^2+b^2)c=a2+b2

c=sqrt(1.84^2+1.84^2)=2.6mc=1.842+1.842=2.6m