Pre-Lab 6A: Newton’s First and Second Laws

Purpose

The relationships between force and motion are known as Newton’s laws.

The First Law explains what happens when there is NO net force on an object,

and the Second Law explains what happens when there IS a net force.

The two laws are closely related. We will focus in this investigation on what happens

to the Energy Car’s motion when you change the force and the mass separately.

Both laws apply!

Key Question

• What is the relationship between force and motion?

Background

Define:

• Newton’s first law of motion

• Inertia

• Provide the formula for the second law of motion

Drawing

Section 1:

• For this first part of the investigation you will use different amounts of force (# of rubber bands) to launch the car.

• you will measure the RESULT of the force and calculate the speed caused by the force of the rubber band.

• Make a formal hypothesis:

What will happen to the speed of the car as the force gets larger?

use the “if…then…because” format.

Section 2:• Put one photogate on the first square mark

after the rubber band.• Put one marble in the center of the car.• Car faces what direction: look at drawing?• Use the screw to launch the car using the

same deflection of the rubber band each time.

• This means the same force is applied to each launch.

• average three launches with times that are within 0.0015 seconds.

• Repeat the experiment with two and three rubber bands.

What is the formula for speed?

Read line 5 (section 2) to determine the distance used

Section 3:• Make a graph showing the speed of the

car on the y-axis and the number of rubber bands on the x-axis.

Section 4:

launch cars with one rubber band and four different masses.

Measure the mass of the car with

0, 1, 2, and 3 steel marbles.

Section 5:

• Use Table 2 to graph the speed of the car (y) against the mass (x).

Section 6 (required):

You will launch the car with one rubber band and no marbles.

Then you will launch the car with TWO rubberbands and TWO marbles in the car.

This means you will double both the force and the mass at the same time.

How will these times compare?

Make a prediction: use the “if…then…because” format.

Post Lab 6A: Newton’s First and Second Laws

Purpose

The relationships between force and motion are known as Newton’s laws.

The First Law explains what happens when there is NO net force on an object,

and the Second Law explains what happens when there IS a net force.

The two laws are closely related. We will focus in this investigation on what happens

to the Energy Car’s motion when you change the force and the mass separately.

Both laws apply!

Key Question

• What is the relationship between force and motion?

Background

Define:

• Newton’s first law of motion

• Inertia

• Provide the formula for the second law of motion

Section 1/2:

What was your hypothesis: if you increase the force (# rubber bands) acting on a car then the speed did what and why?

What was your results: graph: axis, data line: direction/shape?

What part of the motion is the rubber band affecting SPEED?

Section 4/5:

What would you hypothesize: if you hold constant the force (# of rubber bands) acting on a car but you increase the mass of the car then what happened and why?

Graph: axis, data line: direction, description?

How does Newton’s first law explain your results?

Support your theory: does force cause speed or does it cause a change in acceleration (which comes first: the chicken or the egg?) ?

Section 6:

If you double the force and double the mass, what can you expect as an outcome for the motion?

Show how Newton’s second law helps explain this: F = M x A ?