Explanation:
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Answer:
7.53 km
Explanation:
We at given;
Speed of runner; v_r = 8.5 km/hr
Speed of bird; v_y = 17 km/hr
L = 6.4 km
We know that; time = distance/speed.
We are told that the bird starts from 6.4 km from the start and that it flies back to meet the runner after it reaches the finish line. If the total distance back to the runner is x, it means bird distance is 6.4 + (6.4 - x) = 12.8 - x
Thus;
Time of bird(t_y) = (12.8 - x)/17
Thus,
Time of runner(t_r) = x/8.5 hr
To find x, we have to equate the times of the runner and the bird.
Thus;
x/8.5 = (12.8 - x)/17
Multiply both sides by 17 to get;
2x = 12.8 - x
2x + x = 12.8
3x = 12.8
x = 12.8/3
x = 4.27 km
Thus, cumulative distance traveled by bird is; 12.8 - 4.27 = 7.53 km
For finding a momentum p=mv so p=9×2 , P=18
m = mass of the person = 80 kg
M = mass of earth = 5.98 x 10²⁴ kg
R = radius of earth = 6.37 x 10⁶ m
h = height above the earth's surface = 1400 km = 1.4 x 10⁶ m
r₁ = initial distance of the person from the center of earth when on surface = R = 6.37 x 10⁶ m
r₂ = final distance of the person from the center of earth when at some height = R + h = 6.37 x 10⁶ + 1.4 x 10⁶ = 7.77 x 10⁶ m
F₁ = Gravitational force of earth on the person when at surface
Gravitational force of earth on the person when at surface is given as
F₁ = G M m/r₁² eq-1
F₂ = Gravitational force of earth on the person when at some height
Gravitational force of earth on the person when at some height is given as
F₂ = G M m/r₂² eq-2
dividing eq-1 by eq-2
F₁ /F₂ = (G M m/r₁² )/(G M m/r₂²)
F₁ /F₂ = r₂²/r₁²
inserting the values
F₁ /F₂ = (7.77 x 10⁶)²/(6.37 x 10⁶)²
F₁ /F₂ = 1.49
