In a lab experiment, a ball is rolled down a ramp so that it leaves the edge of the tabl – [Free] B19
In a lab experiment, a ball is rolled down a ramp so that it leaves the edge of the table horizontally at speed 𝑣 v, as shown. It then falls a vertical distance ℎ h to the floor and lands a horizontal distance 𝑥 x away from the base of the table. Air resistance is negligible. Which expression gives the speed 𝑣 v of the ball as it leaves the ramp?
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Answer
Projectile Motion: How Far Does a Ball Travel Horizontally?
🔍 Concept Overview
A ball rolls off a table horizontally with initial velocity v and falls from height h. With no air resistance, its motion can be analyzed in two independent parts:
- Horizontal Motion: Uniform (constant velocity)
- Vertical Motion: Accelerated (due to gravity)
📘 Step 1: Vertical Motion (Time to Fall)
Using the equation for vertical displacement:
y = (1/2)gt²
Rearranging to find time t:
t = √(2h / g)
📗 Step 2: Horizontal Motion (Distance Traveled)
Horizontal distance is calculated using:
x = v × t
Substitute the value of t:
x = v × √(2h / g)
📙 Unit Analysis
vin m/shin mgin m/s²
Units for t = √(2h/g) result in seconds, so:
x = m/s × s = m ✅ Correct units for distance
❌ Why Other Options Are Incorrect
- Option A: 2vh/g — Units mismatch and wrong formula
- Option B: 2v²/g — Doesn’t relate to height
- Option C: “None” — Incorrect as one is valid
- Option E: 2h/g — Represents time squared, not distance
✅ Final Answer
x = v × √(2h / g)
This is the correct horizontal distance the ball travels from the edge of the table.