Question

A small block travels up a frictionless incline that is at an angle of 30.0° above the horizontal. The block has speed 4.21 m/s at the bottom of the incline. Assume
g = 9.80 m/s2.
How far up the incline (measured parallel to the surface of the incline) does the block travel before it starts to slide back down?

Answer 1

F=ma=mgsin(theta)
is used to find the acceleration
mass does not matter, as it cancels out
v^2=v0^2 +2ax
plug in:
initial velocity is given as 4.21 m/s,
final velocity is 0 m/s, as it changes direction,
and the acceleration found earlier to solve for x