An eighth-grade class is studying the motion of objects. They have learned the following concepts about motion. Motion occurs when there is a change in the position of an object with respect to a reference point.

While the speed of the object may change at various times during a trip the average speed for the trip is found by dividing the total distance by the total time.

The motion of the object can be changed by varying the amount of net force acting on the object or by varying the mass of the object.

The teacher asked students to design investigations to determine how changing the forces acting on an object or the mass of the object would change its motion.

The materials for the investigation included:

1 - toy cart

3 - 10N weights

1 - pulley

2 - meters of string

One group of students decided to design an investigation to determine how different amounts of mass on the toy cart would affect the speed of the toy cart. They set up their investigation as shown below:

The students performed several trials using different masses in the toy cart (M1). They hung a mass shown as (M2) to pull the toy cart as it dropped.

Below is a table they made to record their results.

What other step do they need to add to their experimental design in order to determine the effect of mass on the speed of the toy cart?

A) Investigate the time it takes a different toy cart to travel for each trial.

B) Determine the total distance the toy cart traveled for each trial.

C) Determine the effect of increasing the force pulling the toy cart.

D) Investigate how much force was used on the toy cart for each trial.

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.

question#1

ans:

cell is the basic unit of organization of all living things. cells are often called the building block of life and it is the smallest unit of life. the study of cell is called cell biology. cell consists of cytoplasm enclosed within membrane, which contain bio-molecules such as proteins and nucleic acid.

two third of cell is water, which means that two-third of your whole body is water. the rest is the mixture of molecules, mainly proteins, lipids and carbohydrates.

question#2

ans:

organ:

an organ is a group of tissues specialized to form a functional unit. an example is the heart in animals.

organ system:

an organ system is a group of several organs whose functions are synchronized to release an effective action in a living organism. an example is digestive system.

question#3

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#4

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system—working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#5

our body works because of the interactions that happen between organs and organ systems.  

for example:  

the heart to regulate blood flow throughout the body. the blood carries oxygen and nutrients to the cells and carries carbon dioxide and waste away from the cells. body systems work together in maintaining a constant internal environment. when this balance is disrupted, the body systems may not function properly, and human health can suffer.   you start to feel bad.

you need more balloons

maybe because its impossible for balloons to lift a whole entire house.