• Support PF! Buy your school textbooks, materials and every day products Here!

A skateboarder hits a ramp

  • Thread starter ideefixem
  • Start date
  • #1
18
0

Homework Statement



A skateboarder starts up a 1.0 m high 30 degree ramp at a speed of 7.0 m/s. The skateboard wheels roll without friction. How far from the end of the ramp does the skateboarder touch down?

The Attempt at a Solution



ramp length=
h=1sin30=1/2
length=2m

v^2=vi^2+2ad
v^2=7^2+2(-9.8)(2)
vf=3.13m/s

vf=vi+a(Dt)
0=3.13+-9.8(t)
delta t=.32s

Xf=xi+vi(dT)
x=0+3.13(.32)
xf=1.0016

yf=yi+vi(dt)+1/2a*(dt)^2
yf=1+0(.32)+1/2(-9.8)(.32)^2
yf=0

The skateboarder lands 1.0016 meters from the end of the ramp.




I know I'm missing something somewhere... can someone please help me find it.
 

Answers and Replies

  • #2
18
0
Hmm... That wasn't even close... Let me try this again.

cos30(7)=vx= 6.06 m/s
sin30(7)=vy= 3.5 m/s

-1=3.5(t)+.5(-9.8)(t^2)
0=-4.9t^2+3.5t+1
t= 0.933 s

x= (6.06)(.933)+.5(0)(.933)^2
x= 5.65 m

How does that look?
 

Related Threads for: A skateboarder hits a ramp

Replies
11
Views
7K
Replies
2
Views
1K
Replies
4
Views
2K
Replies
2
Views
4K
  • Last Post
Replies
2
Views
3K
  • Last Post
Replies
2
Views
493
Replies
11
Views
3K
Replies
0
Views
1K
Top