Review:

Newton’s First Law: If the Net Force on an object is zero, it will not accelerate.

If an object is at rest, it will remain at rest. If an object is in motion, it will move with constant velocity, that is, at constant speed in a straight line.

Newton’s Second Law: If the Net Force on an object is not zero, it will accelerate in the direction of the net force.

Equations of Motion

Velocity includes direction indicator, usually a + or – sign.

Part 1 Newton’s 1st and 2nd Law of Motion

Open PhET Simulation Forces and Motion, Basics (see Canvas).

Link: https://phet.colorado.edu/sims/html/forces-and-motion-basics/latest/forces-and-motion-basics_en.html

Select the 4th window labeled Acceleration twice.

Leave Friction setting at the default position.

Check all the boxes.

Using the arrow keys gradually apply a force to the right on the crate and determine the maximum force that can be applied without overcoming the force of static friction to start the crate moving. Once the crate starts moving, pause the simulation.

What was maximum force of static friction?

What was the force of kinetic friction once the crate starts moving?

What applied force got the crate moving? (this should the the current applied force setting)?

What is the net force on the crate?

What is the acceleration of the crate?

Show that this demonstrates .

Remember to provide units for all numbers and use a negative sign to indicate vector quantities that point left.

Reduce the force until the net force (labeled “sum of forces” in the simulation) equals zero.

What is the acceleration of the crate now?

These tests should verify important aspects of Newtons’ 1st and 2nd Laws of Motion.

Part 2 Gravity

Open the simulation. See Canvas for the link.

https://phet.colorado.edu/sims/html/gravity-force-lab-basics/latest/gravity-force-lab-basics_en.html

How does the force exerted by the small mass on the large mass compare to the force exerted by the large mass on the small mass?

Put an X in the left next to the correct answer.