Homework 12/1

(1) The acceleration is equal to the net forces over mass. This means that you would put 30 N over 20 kg of the sled. the acceleration would then equal 1.5 m/s.

(2) in 3 seconds the speed is the net force at 3 seconds which is about 1/3 of the 30 which is equal to 10N over the mass which is 20 kg. this would equal .5 m/s.

(3) You need to exert a constant force on the sled to keep it moving at constant speed. This means that you have to keep applying 30 N onto the sleigh in order for it to move at a constant velocity.

Force diagrams:

the sled is the object of interest. The sled is the center dot. There is an arrow drawn in the negative direction (vertically) that is equal to one drawn from the dot in a positive direction (vertically) they are labeled F(Earth on sled) and F(ground on sled) respectively. Then there is an unbalanced force from the right of the object labeled F(pulling on sled) and 30N.

Homework 11/25

1. What pattern did you observe between the unbalanced force exerted on an object of interest and the acceleration of the object of interest?

2. Can you provide a real life example where you can see this phenomenon? (not student A pushing on student B)

1. If an unbalanced force acts upon an object of interest, the acceleration of the object of interest increases.

2. A real life example would be if im sledding down a hill with my friends and instead of us just "riding" out the snow, if we get a push our sled ride would be much faster and much more enjoyable.

Journal 11/20

the object of interest is drawn as a dot to show where and how and what forces are acting on the object of interest. You know how long to draw the arrows by reflecting for a moment and figuring out balanced and unbalanced forces. The man is not touching the crate, therefore he exerts no force onto the crate. By viewing a complete force diagram, you can see which way the object of motion is moving and how much force is being exerted on it. You cannot tell the velocity of the moving object of interest, initial position or acceleration. You know that the bowling ball is moving in the right (positive) direction. You know that the stick is pushing the bowling ball. However, you cannot tell how fast the bowling ball is moving where it started or how much force is being exerted on it.

6. What do you know (and what do you NOT know) about the MOTION of the object shown in the force diagram below?

Journal 10/29

What do you know about the area between the line and the horizontal axis in a velocity versus time graph?

The area between the line and the horizontal axis in a velocity versus time graph is the displacement.

Which car has the greatest change in position from 3-5 seconds?

the pink car has the greatest change in position from 3-5 seconds.