Elastic Collisions

A moving skateboard. Since momentum is mass times velocity, the train has no momentum since its velocity is zero. Because default a moving skateboard, no matter how fast its moving, has to have a greater momentum.

Elastic vs. Inelastic

An inelastic collisions occurs when two objects collide and do not bounce away from each other.
An elastic collision occurs when the two objects "bounce" apart when they collide.





A car's bumper works by using this principle to prevent damage. In a low speed collision, the kinetic energy is small enough that the bumper can deform and then bounce back, transferring all the energy directly back into motion.





In an elastic collision, both momentum and kinetic energy are conserved.

Work vs. Power

Work is usually defined as a force moving through a distance 
So power would be the rate at which the work gets done.

work is the action...power is the result


      he is doing more work with more power because he is lifting the box higher and the box is heavier, so there for he needs more power in order to pick it up.



he is doing less work because he isn't lifting the  box that high and the box isn't heave there for it needs lest power in order to lifted up.

Mass and Newton’s 1st Law

this pictures shows the correlation between inertia and Newton’s 1st Law, and the amount of mass something has , well because as you can read in the pictures it says that with no outside forces, this object will move.
                                                                                             



                                                                                            This tree examples shows the correlation                                                                                                      between inertia and Newton’s 1st Law, and the                                                                                                amount of mass something has because small                                                                                                amount mass the larger the acceleration and                                                                                                  the lager amount of mass the smaller the                                                                                                         acceleration. This pictures shows that.
this picture shows the correlation between inertia and Newton’s 1st Law, and the amount of mass something has because if the ball had more mass the girl have to kicked harder in order for the ball to go far.



This picture shows the correlation between inertia and Newton’s 1st Law, and the amount of mass something has because it showing how the both object have the same force but they are going in different speed because one object have more mass then the order.

Inertia Investigation

 when i'm playing ball with my little brother in the park , the ball some times goes to this down hill but that down hill goes up after so therefor the ball goes back and front it never stops because there is no friction force.




 As you see this ball is stopping really quickly because there is fiction acting upon it. This means that something else is stopping the ball

Mass and Newton’s 1st Law

three examples in my life that show the correlation between inertia and Newton’s 1st Law,

             (pulling a tablecloth)

  when you're pulling a tablecloth the staff that is on it whats to stay the same. you are pulling only the cloth in order for the staff on top to not move you have to pull the cloth very fast (velocity)

               (eureka-mass)

the amount of mass doesn't depend on size.

Mu - Friction

Friction happens when one object slides along another object. It is the force that resists the relative motion between the two surfaces. Friction occurs in the opposite direction of the moving object's motion and reduces its speed.
                 names of another surface that i think would have an even bigger value of μ with my shoe. 
                                        *wood floor
                                        *ceramics floor
                                        *glass
                                        *plastic 
                                     

Free Body Diagrams

                          

                          FN=-8N

                                                     FG=8N

                                                      FF=-5N

                                                      FA=5N

the block is not moving since all the forces have the same amount. I'm pushing the block with both hands and my sister is pulling the block too. Which means that i will be the applied force and my sister is the friction force. The normal force would be the table where is at which is going against gravity force .The gravity force which is pulling the block down.

Balanced and Unbalanced

    Balance: the net force equal zero.
   Unbalance: the net force doesn't equal zero.
               (this all are unbalance)
                        
                              - applied force
                              - tension force
                             


                      (this is balance)
                            



                   

Vectors & Scalar

       The difference between vector and scalar is that in scalar the direction doesn't matter and in vector the direction does matter.  

  

Acceleration

       Acceleration: a change of velocity (speed or direction)

      A sports car and a school bus are stopped at a traffic light.
The differences and the similarities of the motion of these two vehicles are that, the bus school have to change in speed way before the traffic light in order to stop in the indicated position, and the sports car can stop a little before the traffic light but that depends on the speed its going.

Four Forces

 *Applied force: to push or pull that is caused by a person or think.
  *Gravitational force: a force attracting two objects.
  *Normal force: a force that pushes up against gravity.
  *Tension force:a pulling force, in a rope, string,etc.

GUESS Method

      The  5 steps of the GUESS Method are the following:  

        - Given: the information in the problem.

        - Unknown: the variable you are trying to find.

        - Equation: the formula you'er going to use.

        - Substitute: the substitution of the information into the

            equation.

        - Solve: the solving of the equation, your result.    

Distance vs. Time Graphs

Today in class we did this type of graph that graphed you motion . We had to use detector that detected you. I think that  these graphs would be necessary in our science class because we will be graphing motion and does graph are perfect to graph motion.

Distance vs. Displacement

Distance is the total traveled.     .                  .
                                                             distance


Displacement is the distance between the start position and the end position.

Barbie Bungee Data Estimates

I think that the drop distance would be 163cm if we hand 10 rubber bands. If we had 20 rubber bands the drop distance would be about 207cm. If we had 30 rubber bands i think that the drop distance would be around 350cm. I estimated     the drop distance see the data that we got when we had 8 rubber bands. And jest by comparing the data we  got and the jest estimate the drop distance.

Metric Units

    I think we use metric in science class instead of english units because is easier to measure with.

         Things that has metric units...
                           
                                          -the refrigerator 
                                          -the stove
                                          -the table
                                          -the doors

Estimating Distance

    My estimate of the length of the front of my house is about 7.5 meter.

1. I had to see how many feet are in a meter

2. Measured the sidewalk planks

1 meter=100cm                 1 meter is going to be 3 ruler +10cm

ruler=30cm                 

In front of my house there are 5 blocks and every block = to 5 feet...

5 x 5 =25            30 x 25 =750            7.5

                                           

         I think that this is a reasonable estimate because the front of my house is not the big , so yeah.                                  

Reaction Time

     Reaction time is the way you react and how fast you react. 
When i'm playing soccer and they pass me the ball my reaction have to be fast , because if i don't react fast somebody  else is going to take it away from me, you do not want that to happen. When you are drinking very hot coffee and is about to fall you better react fast to that because that really burns and you have to react smartly because if you react stupidly you might spill some more. When you are distracted and someone calls your name and you look and a baseball ball is coming directly to your face you have to react quickly if you don't want the ball to hit you.