Question

A ball is thrown upward at an angle of 37⁰ to the horizontal and lands on the the top edge of a building that is 20m away. the top edge is 10m above the throwing point. how fast was the ball thrown?​

Answer 1

Given:-

• A ball is thrown upward at an angle of 37⁰ to the horizontal and lands on the the top edge of a building that is 20m away.
• The top edge is 10m above the throwing point

ToFind:-

• How fast was the ball thrown?

Solution:-

By using trajectory formula for projectile motion

→ y = x tanθ - (gx²/2u²cos²θ)

Where,

• y = 10m
• x = 20m
• θ = 37°
• g = 9.8m/s²
• u = initial velocity
• tan37° = 3/4
• cos37° = 4/5

Putting the values

→ 10 = (20×tan37°) - 9.8×(20)² / 2u²cos²37°

→ 10 = (20×¾) - 3920 / 2u²×(⅘)²

→ 3920 / 2u²× 16/25 = 15-10

→ 245×25 / 2u² = 5

→ 2u² = 245×25 / 5

→ 2u² = 1125

→ u² = 1125/2

→ u = 24.74 m/s

Hence,

• The ball was thrown at 24.74 m/s