What is the horizontal position after t = 3 s with v0x = 5 m/s?

What is the horizontal position after t = 3 s with v0x = 5 m/s?

• A. 5 m
• B. 8 m
• C. 18 m
• D. 15 m

Answer: (D)

Horizontal motion with constant velocity means the horizontal position changes by velocity times time. The position is x = x0 + v0x t. If we start at the origin, x0 = 0, and v0x = 5 m/s for t = 3 s, then x = 0 + (5 m/s)(3 s) = 15 m. So the horizontal position after 3 seconds is 15 meters. The other numbers would require a different starting point, a different time, or a different velocity.

Horizontal motion with constant velocity means the horizontal position changes by velocity times time. The position is x = x0 + v0x t. If we start at the origin, x0 = 0, and v0x = 5 m/s for t = 3 s, then x = 0 + (5 m/s)(3 s) = 15 m. So the horizontal position after 3 seconds is 15 meters. The other numbers would require a different starting point, a different time, or a different velocity.