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1.

a. Work is using any type of force to move something.

b. A machine is a mechanical device that handles work. They make it easier to do the work.

2. The answers A , B and C all work because in each action you are moving something by using a force. In D, you're not doing work because you dont use a type of force to read.


3. Because food gives you energy, and you need energy to be able to handle work.

4. Spanners, pliers, and can openers, are called machines because they make work easier.

5. scissors and hammers.

pg 81

1. Pulleys wheels and a rope.

2. you can lift the engine up by pulling down on the rope which is far more easier than a human picking a car up. Also a pulley supports the car equally.

3.

a. The chain passes on the force to the back wheels, turning them.

b. The cycle gears change the number of times that one turn of the crankshaft turns the back wheels.

4. The different gears have different amounts of forces. The higher gear can be used in flat surfaces because there is enough force to make the wheels spin. if you were going up a hill you need to shift it to low gear because the high gear doesnt have enough amount of force to make the wheels spin up a hill.

After watching the movie Erin Brockovich and researching further into it, i learned that we humans have to be careful and aware of what is goung around of us. It had changed my perspective of water. You have to be careful and aware of where the water you're using or drinking is coming from. Also the companies we have should be vary careful with the chemicals they use. They could be harming us without even knowing it just like PG&E did to the town of Hinkley. I think that people should take this movie into account. It is a good way to make people aware that things like that could be happening in their town.

Questions on Forces

What is a force?

A force basically is a push or a pull. It is the acceleration of any mass.

Examples of Forces:

Tension: A force that stretches something.

Gravity: The attraction between all masses in the universe. Gravity on earth pulls all masses to the center or close to it.

Friction: The resistance when one thing is is moved in contact with something else.

Magnetic: A force that pulls ferromagnetic objects and repels or attracts other magnets.

What units are forces measured in?

They are measured in newtons.

What is the equation that is used to calculate a force?

force=mass x acceleration

1.
a. consumers
b. large predators
c. small predators
d. no one

2. the population of the lizards and other grazers in the state will increase and coyotes will be endangered.

3. the amount of mountain lions will increase and because of that pronghorns and other gazers will be endangered and may come to an end.

4. If mesquite trees were introduced to this ecosystem some effects would be:
-some types of primary consumers may not be able to grow because they take up a lot of water
-primary consumers and omnivores will have more food to eat from
-the soil in the area will be renewed which will allow other plants to grow again and this time they'll be much healthier and they will grow better