Saved Bookmarks
| 1. |
A ball is dropped from a balloon going up at a speed of 5 m/s. If the balloon was at a height 60 m. at the time of dropping the ball, how long will the ball take to reach the ground? (Ans: 4s) |
|
Answer» Given conditions ⇒ Initial Speed of the ball(u) = -5 m/s. [Since, ball is dropped from the BALLOON]. Height of the balloon = 60 m. Acceleration DUE to GRAVITY = 9.8 m/s² Using the Formula, S = ut + 1/2at² ⇒ 60 = -5t + 1/2 × 9.8 × t² ⇒ 60 = -5t + 4.9t² ⇒ 4.9t² - 5t - 60 = 0 ∴ 49t² - 50t - 600 = 0 This is TH quadratic equation. If we solve it by the methods of the quadratic Formula, we wlil get, t = - 4.02 and t = 3.03 seconds. Since, time cannot be negative. Hence time will be 3 seconds. Hence, the time taken by the ball is 3.02 seconds. Hope it helps. |
|