Find speed of object traveling up a ramp

[PhysicsGirl]

Homework Statement

An object approaches the bottom of a ramp, point A. It goes up the ramp and turns around at point B, which is 40.0 m above A. The ramp makes an angle of 30.0 degrees with the horizontal. What is the speed of the object at point A? Neglect friction.

Homework Equations

g=10.0 m/s (squared)

The Attempt at a Solution

I did 2cos(30)40

 

[mgb_phys]

I would use conservation of energy - assuming you read the question to say it has stopped at point B.
Write the kinetic energy of the object at the start of the ramp
At the top of the ramp all this ke is pe, write down the equation for PE.

 

[Moetasim]

.0=69.2820323 meters.

Using the equation v^2 = u^2 + 2as, where v is the final velocity, u is the initial velocity (which we assume is 0 since the object starts at rest at point A), a is the acceleration due to gravity (g=10.0 m/s^2), and s is the displacement (69.2820323 m), we can solve for the final velocity at point A.

v^2 = 0^2 + 2(10.0)(69.2820323)
v^2 = 1385.640646
v = √1385.640646
v = 37.20 m/s

Therefore, the speed of the object at point A is 37.20 m/s.