- #1
physics_noob2
- 2
- 0
Homework Statement
A projectile starts from rest and moves 4.7 m down a frictionless ramp inclined at 21 degrees with the horizontal. the acceleration due to gravity is 9.8 m/s^2
what what speed will it leave the ramp ?
what will the range of the projectile if the bottom of the ramp is 2.1 m above the ground
Homework Equations
V=Vi + at
delta X = Vi*t+1/2 a*t^2
Vf^2 - Vi^2 = 2*a*deltaX
The Attempt at a Solution
Vertical,
Viy=0
ay=-9.8
Vfy= - Vf sin 21
delta y= -4.7 sin 21
horizontal,
Vix= ( i thought it to be zero at first but it can't be zero because then the delta x comes out to be zero. So I am confused at this one )
ax=0
Vfx=Vf cos 21
delta x= 4.7 cos 21
so i used the third law and set it up as follows,
Vfy^2 = 2 (-9.8) (4.7 sin 21)
then the idea is to set the answer = Vf sin 21 and solve for Vf
it comes out to be 16.0329
but this is unfortunately not the right answer. can anyone help ?