The force that causes the puck to decelerate is the component of its weight that is parallel to the ramp.

Force parallel = 0.12 * 9.8 * sin 27 = 1.176 * sin 27

This is approximately 0.534 N.

a = -9.8 * sin 27

This is approximately -4.45 m/s^2. Since we know the length of the ramp, we can use the following equation to determine its minimum speed.

vf^2 = vi^2 + 2 * a * d, vf = 0

0 = vi^2 + 2 * -9.8 * sin 27 * 4.2

vi^2 = 82.32 * sin 27

vi = √82.32 * sin 27

This is approximately 6.1 m/s. I hope this is helpful for you.

½mV² = mgh

V² = 19.6*4.2*sin27 = 6.1²