Question

A free-falling projectile is launched from the ground and has a hangtime of 6 seconds before hitting the ground. How high did it go?

Answer 1

1A)  

x=v0x*t=v0cosθ*t  

x=52co31*3.2=142.6 m  

1B)  

y0=1/2gt^2-v0y*t=1/2gt^2-v0sinθt  

y=0.5*9.8*3.2^2-52*sin31*3,2=23.4 m  

2A)  

x=2v0^2sin(2θ)/g  

v0=[xg/2sin(2θ)]^1/2=14.4 m/s  

the initial speed relative to the ground is  

v=v0-4.4=10 m/s  

2B)  

fly time is  

t=2voy/g  

t=2*14.4/9.8=2.94  

2C)  

mgy=1/2mv0y^2  

y=v0y^2/(2g)=10.58 m