projectile motion question (1 Viewer)

[asb_92]

hey guys
was jus wondering could someone please help me with this problemm...
i havnt done projectile in ages and cant seem to work it out ><
thankss in advance

"A projectile is fired at an angle of 30* to the horizontal from a tower 20m high. the projectile takes 10s to hit the ground. calculate the initial speed of the projectile."

 

[kaz1]

s=ut +1/2.a.t²
20=vsin30(10) +4.9(100)

Solve that and you should get it.

 

[k02033]

should be Sy=0 when t=10



notice once i subtitude for Sy and t, i have one equation, one unknown ---> solvable





rearrange for Uy

 

[asb_92]

ahhk cool!
thanks