Projectile motion problem. (1 Viewer)

[VuongstER_boi]

Hey guys, does any know how to do the following question on projectile motion:

A projectile has a range of 750m and reaches a maximum height of 58.8 m above its launch point.

(a) What is its time of flight?
b) What is its launch velocity?


I have to present this tomorrow but I'm so confused what formula you gotta use...so yeah..thanks =).

 

[FLYHAWK14]

Well, for this problem although I've already worked it out and found the answers, you're probably going to use a range of formulas, even at some points you have to solve simultaneously. Well here they are:

First you substitute this data into: Vy^2=Uy^2+2ayΔy
Vy^2=0
Uy^2=?
ay=-9.8
Δy=-58.8
solve for Uy
#2-Vy=Uy+ayt
Vy=0
Uy=result above
ay=above
t=750/Ux(range formula)
solve for Ux
From this you can find launch velocity from pythagoras' theorem with Ux and Uy

For time of flight
Δx=Uxt

Δx=750m
Ux=result above
t=???

Hope that helps.

 

[VuongstER_boi]

yeah, thanks!!