Newtons Law / Kinematic problem?

[physstudent1]

Hello, the question I'm having trouble with is:

"A 8.00kg block of ice, released from rest at the top of a 1.5 m long frictionless ramp, slides downhill, reaching a speed of 2.5 m/s at the bottom.
What is the angle between the ramp and the horizontal?"

My first attempt to solve this problem was that I would use kinematics to get the acceleration. And then use the acceleration and Newton's laws to find the angle. By using kinematics I got the equation 2.5^2 = 0 + 2(a)(1.5)
I then got a to be 1.64. Using that I set the equation 8gsin(theta) = 1.64(8). Eventually getting theta to equal 9.6 degrees. But when I compared my answer to the a fellow classmate He got 12.275, but I can't really follow his work and there's no answer in the back of the book, so can anyone help?

 

[Hootenanny]

Since there is no friction, it may be easier to consider this problem as a conservation of energy problem.

 

[physstudent1]

We have not gotten to energy yet in my class :(. This is the third chapter all we have done is kinematics, projectile motion, and now this.

 

[Hootenanny]

I've just looked through your work and it appears it's just your arithmetic that's letting you down. Your kinematic equation is correct, but your value for acceleration is not; try solving for acceleration again.

 

[physstudent1]

Ah jeez I'm so dumb thanks a lot! I just have sloppy hand writting so I turned the 1.5 into a 1.9 which gave me the wrong answer thanks a lot.