Answer:
The "distance" is the answer to the question,
Explanation:
99.0km/h =27.5m/s (this is the initial speed)
The final speed is zero
The distance is 50.0m
Therefore you use the formula:
vfinal²=vinitial²+2ad
a=(vfinal²-vinitial²)/2d
= (0²-27.5²)/(2x50.0)
=-7.5625 or in correct sigdigs -7.56m/s²
Hope this helps!
Use the law of universal gravitation, which says the force of gravitation between two bodies of mass <em>m</em>₁ and <em>m</em>₂ a distance <em>r</em> apart is
<em>F</em> = <em>G m</em>₁ <em>m</em>₂ / <em>r</em>²
where <em>G</em> = 6.67 x 10⁻¹¹ N m²/kg².
The Earth has a radius of about 6371 km = 6.371 x 10⁶ m (large enough for a pineapple on the surface of the earth to have an effective distance from the center of the Earth to be equal to this radius), and a mass of about 5.97 x 10²⁴ kg, so the force of gravitation between the pineapple and the Earth is
<em>F</em> = (6.67 x 10⁻¹¹ N m²/kg²) (1 kg) (5.97 x 10²⁴ kg) / (6.371 x 10⁶ m)²
<em>F</em> ≈ 9.81 N
Notice that this is roughly equal to the weight of the pineapple on Earth, (1 kg)<em>g</em>, where <em>g</em> = 9.80 m/s² is the magnitude of the acceleration due to gravity, so that [force of gravity] = [weight] on any given planet.
This means that on this new planet with twice the radius of Earth, the pineapple would have a weight of
<em>F</em> = <em>G m</em>₁ <em>m</em>₂ / (2<em>r</em>)² = 1/4 <em>G m</em>₁ <em>m</em>₂ / <em>r</em>²
i.e. 1/4 of the weight on Earth, which would be about 2.45 N.
First you need to calculate the velocity of the stone when it reaches the ground level. This is easy to find from energy conservation, since the potential energy it had at the top of the tower has been totally converted into kinetic energy.
We don't know the mass of the stone, but it cancels from both equations. This gives
so v=44.27 m/s.
Now, the time it took the stone to fall from the top of the tower to the ground is calculated easily from
.
The initial velocity is 0, the initial height is 100 meters and the final height is 0 since we are taking the ground floor as height 0.
This gives
So the time it took the stone to fall from the ground level to the bottom of the well is 5-4.52=0.48 s.
We can now use
where v is the velocity we calculated before v=44.27 m/s, time is t=0.48 s and xf is the depth of the well.
So the solution is 22.5 m