What is MASS?

• How much matter (atoms) an object has

• The more atoms an object has, the more MASS it has

• An object has the same MASS no matter where it is.

  • Ex.  The same rubber ball will have the same number of atoms if it is on the Earth or on the moon.

What is ACCELERATION?

• Change in how fast an object moves.

• An object can:

  • Speed up (often called acceleration)

  • Slow down (often called deceleration)

What is FORCE?

• ACCELERATION of a MASS in a certain direction.

           

  • FORCE = MASS X ACCELERATION

     

    Note how the blue FORCE arrow pushes on the red ball (MASS) to cause it to move.  Because the FORCE is continually acting on the ball, the speed of the ball increases (ACCELERATES) as the ball moves across the white space.  The FORCE (blue arrow) acts on the MASS (red ball) to make it ACCELERATE across the screen.

• FORCE is additive.

  • If two forces are working against each other on an object, they may cancel each other out so the object does not change position. 

     

    

     

    Note how both the blue and the green FORCE arrows are pushing on the ball.  However, since they generate the same amount of FORCE in opposing directions, they cancel each other out and the ball does not change position.

     

  • If two forces are working together on an object, they will have a bigger effect together on the object than either would separately.

     

    

     

    Note how the top ball is only being pushed by the blue FORCE arrow while the bottom ball is pushed by the blue and the green FORCE arrows.  The blue and green FORCES add up to make the bottom ball ACCELERATE more than the top ball.

   

How do FORCE, MASS and ACCELERATION interact?

• ACCELERATION and MASS both contribute to FORCE.

• FORCE also contributes to ACCELERATION.

  • The more FORCE applied to an object, the faster it will ACCELERATE.

     

    

     

    Note how the top ball is being pushed by the small blue FORCE arrow while the bottom ball is pushed by the larger green FORCE arrow.  The larger green FORCE makes the bottom ball ACCELERATE more than the top ball.

   

  • The more MASS an object has, the more FORCE is needed to ACCELERATE.

     

    

     

    Note how the blue and green FORCE arrows are the same size, but the bottom ball is bigger than the top ball.  The bottom ball has more MASS than the bottom ball, so the green FORCE arrow is not able to ACCELERATE the bottom ball as quickly as the blue arrow ACCELERATES the top ball.  More FORCE would be needed to ACCELERATE the larger MASS as quickly as the smaller MASS.