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Homework Help

Homework Help team will assists public, private and home schooled students, grades 4-12, with their homework assignments. Our professional team will help student with their homework while they develop the basic skills to tackle similar type of problems. Since students from same grade will have different level of understanding, our team work with their ynderstanding capacity and design strategies to teach them accordingly. Each student is given special attention with focus to develop basic skill and expertise towards academic excellence.

Our Answers to Your Questions

We all enjoy the colors of autumn leaves. Why Do Leaves Change Color in the Fall?

Plant have to make their own food. Leaves are nature's food factories. Plants take water from the ground through their roots and take gas called carbon dioxide from the air. Plants use sunlight to turn water and carbon dioxide into glucose. Glucose is a kind of sugar, used as food for energy and as a building block for growing. The way plants turn water and carbon dioxide into sugar is called photosynthesis (putting together with light). A chemical called chlorophyll present in the leaves helps make photosynthesis happen. Chlorophyll is what gives plants their green color.

As summer ends and autumn starts, the days get shorter and shorter. This is how the trees "know" to begin getting ready for winter. During winter, there is not enough light or water for photosynthesis. The trees will have to rest, and live off the food they stored during the summer. They begin to shut down their food-making factories. The green chlorophyll disappears from the leaves. As the green fades away, we begin to see yellow and orange colors. Small amounts of these colors have been in the leaves all along. We just can't see them in the summer, because they are covered up by the green chlorophyll.

The bright reds and purples we see in leaves are made mostly in the fall. In some trees, like maples, glucose is trapped in the leaves after photosynthesis stops. Sunlight and the cool nights of autumn cause the leaves turn this glucose into a red color. The brown color of trees like oaks is made from wastes left in the leaves.

It is the combination of all these things that make the beautiful colors we enjoy in the fall.

Why is the force of gravity on the moon less than on earth?

Newton's equation for the force of gravity between two objects is: F = G*m1*m2/d^2 (units of "Newtons") where

m1 and m2 are masses (in kilograms); Mass of the Earth: 5.98 x 10^24 kg; Mass of the moon: 7.34*10^22 kg
d^2 is the distance (in meters) squared between the centers of the two objects (e.g. you and the center of the earth); Radius of the Earth: 6378 km; Radius of the moon: 1737.4 km
G is a constant, the gravitational constant, which is 6.67*10^-11 when these units are used. Since this is a very small number, it means that gravity is a very weak force that you only really notice when there is a very large mass involved (like the earth or the moon).
Suppose you weigh 140 pounds, your mass would be 63.5 kg

The force of gravity between you and the earth is: F = 620 N

F = (6.67*10^-11) (5.95*10^24 kg)(63.5 kg)
---------------------------------------
(6,378,000 m)^2

The force of gravity between you and the moon is: F = 103 N

So, the force of gravity on a person on the earth is greater than the force of gravity on a person on the moon.

In simple words, the force of gravity on the moon less than on earth because mass of the moon is less than that of the the earth.