Question

Тело брошено вертикально вниз с высоты 20 м. Сколько времени оно будет падать и какой будет скорость в момент удара о землю ?

Answer 1

H=gt²/2
t=$\sqrt{2h/g}$
t=$\sqrt{2*20/10}$=2c
2gh=V²
V=$\sqrt{2gh}$
V=$\sqrt{2*20*10}$=20м/с

Answer 2

Time and Velocity of a Body Falling Vertically

When a body is thrown vertically downward from a height of 20 meters, we can calculate the time it takes to fall and the velocity at the moment of impact using the following formulas:

1. Time of Fall (t): - The time it takes for the body to fall can be calculated using the formula: \[ t = \sqrt{\frac{2h}{g}} \] where \( h = 20 \, \text{m} \) (height) and \( g = 9.8 \, \text{m/s}^2 \) (acceleration due to gravity).

- Substituting the given values, we get: \[ t = \sqrt{\frac{2 \times 20}{9.8}} \] \[ t \approx 2.02 \, \text{s} \]

- Therefore, the time it takes for the body to fall is approximately 2.02 seconds.

2. Velocity at Impact (v): - The velocity of the body at the moment of impact can be calculated using the formula: \[ v = gt \] where \( g = 9.8 \, \text{m/s}^2 \) (acceleration due to gravity) and \( t \) is the time calculated previously.

- Substituting the value of \( t \), we get: \[ v = 9.8 \times 2.02 \] \[ v \approx 19.96 \, \text{m/s} \]

- Therefore, the velocity of the body at the moment of impact is approximately 19.96 m/s.

In conclusion, the body will take approximately 2.02 seconds to fall and will have a velocity of approximately 19.96 m/s at the moment of impact with the ground.