Question

From a hot air balloon that is at rest at a certain height, a projectile is launched horizontally at 30m / s, how fast will it have after 4s?

A. 50m / s
B. 60m / s
C. 70m / s
D. 80m / s

Answer 1

A. 50 m/s

Step-by-step explanation:

Given in the y direction:

v₀ = 0 m/s

a = 10 m/s²

t = 4 s

Find: v

v = at + v₀

v = (10 m/s²) (4 s) + 0 m/s

v = 40 m/s

In the x direction, the velocity is constant at 30 m/s.

The overall speed is:

v² = (30 m/s)² + (40 m/s)²

v = 50 m/s