Answer:
2.7 m/s
Explanation:
Draw a free body diagram of the ball. There are two forces:
Weight force mg pulling down
Tension force T pulling 39° above the horizontal
Sum of the forces in the y direction:
∑F = ma
T sin θ − mg = 0
T = mg / sin θ
Sum of the forces in the radial (+x) direction:
∑F = ma
T cos θ = m v² / r
Substitute:
(mg / sin θ) cos θ = m v² / r
mg / tan θ = m v² / r
g / tan θ = v² / r
v = √(gr / tan θ)
Given that r = 0.6 m and θ = 39°:
v = √(9.8 m/s² × 0.6 m / tan 39°)
v ≈ 2.7 m/s
This is false, materials that are poor conductors must be good insulators.