You then decide to throw another disc to your friend in the tree for fun. If you throw the disc at a speed of 10 m/s and your friend catches it 5.0 m above you, what was the speed of the disc just before your friend catches it

Vf = 1.41 m/s

Explanation:

The velocity of the disc just before the friend catches it, can be found out by using 3rd equation of motion, as follows:

2gh = Vf² + Vi²

where,

g = - 9.8 m/s² (negative sign for upward motion)

h = height = 5 m

Vi = Initial Velocity = 10 m/s

Vf = Final Velocity = ?

Therefore,

2 (-9.8 m/s²) (5 m) = Vf² - (10 m/s) ²

Vf² = 100 m²/s² - 98 m²/s²

Vf = √ (2 m²/s²)

Vf = 1.41 m/s