Calculating Time and Velocity in a Projectile Motion Problem

[Rubix]

3rd week in AP physics... can't figure this out :'(

Homework Statement

delta X = 20m
delta Y = -1.5m
angle = 10 degrees

basically, a car goes off a 10 degree ramp and lands 20 meters away and the delta Y is 1.5m... my assumption is that I need to find T first.

Homework Equations

we are given 4 equations:
delta X = VxoT
Vy = Vyo + AyT
delta Y = VyoT + (1/2)AyT^2
Vy^2 = Vyo^2 + 2Ay(delta Ymax)

The Attempt at a Solution

i have no attempt.

 

[rock.freak667]

y=y₀+v_xt-1/2gt²

you want to find t when y=0 (y₀=1.5)

 

[Rubix]

y=y₀+v_xt-1/2gt²

you want to find t when y=0 (y₀=1.5)

I don't know what Vx is.

 

[rock.freak667]

I don't know what Vx is.

the angle θ=10

so v_x=vcosθ

and v_y=vsinθ


Also I made a typo,the equation should be


[tex]y=y_0 +v_y t -\frac{1}{2}gt^2[/tex]


(not v_x in it)

 

[Anden]

A hint: You must plug one equation into another on this one, this will result in the removal of Vo from an equation and leaving only time.

 

[Rubix]

I still need help, I know i need to plug in equations into each other but I'm not sure which ones

 

[Rubix]

figured it out, the key was

t = (20.33/v)

then i plugged that into this eqn:

delta X = VxoT