- #1

- 76

- 0

i dont know how to compute this without the angle

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter Sucks@Physics
- Start date

- #1

- 76

- 0

i dont know how to compute this without the angle

- #2

Doc Al

Mentor

- 45,140

- 1,443

What's conserved?

- #3

- 21

- 0

E = m*g*(change in height)

E = 60*9.81*20 = 11772 J

So skier loses 11772 J of potentiaql energy on descent, this is all converted into kinetic energy. So using KE formula :

KE = 0.5*m*(v^2)

V = sqrt(KE/0.5*m) = 19.81 m/s

So add the initial velocity to this to get :

5 + 19.81 = 24.81 m/s

- #4

Doc Al

Mentor

- 45,140

- 1,443

(1) Please reread the forum rules about posting complete solutions.

E = m*g*(change in height)

E = 60*9.81*20 = 11772 J

So skier loses 11772 J of potentiaql energy on descent, this is all converted into kinetic energy. So using KE formula :

KE = 0.5*m*(v^2)

V = sqrt(KE/0.5*m) = 19.81 m/s

So add the initial velocity to this to get :

5 + 19.81 = 24.81 m/s

(2) This solution is not correct.

- #5

- 76

- 0

The books says the answer is 20m/s?

- #6

Doc Al

Mentor

- 45,140

- 1,443

Use conservation of energy, but be sure to apply it correctly.

- #7

- 76

- 0

KE = 0.5*m*(v^2)

I'm not exactly sure how to manipulate the KE formula to where it will come up with a reasonable answer

- #8

Doc Al

Mentor

- 45,140

- 1,443

That's theE = 60*9.81*20 = 11772 J

- #9

- 76

- 0

final = 12522J

so v^2 =12522J/(.5*m) = sqrt 417.4 = 20.4

And do you not add the initial push off speed since you used it to get the initial KE?

- #10

- 73

- 0

- #11

- 76

- 0

sweet, thanks

Share: