PREPARED BY

BAGAS SINGA, FAIZAN KHAN AND JOHNATHAN

ZANG

TEACHER: MR.SHAIKH

COURSE: SPH4U0

DATE: 15/12/2014

THE MOUSETRAP FINAL SUMMATIVE

PROJECT

TABLE OF CONTENTS

1. ABOUT THE MOUSETRAP CAR …………………………………………………………………P.2

2. RESEARCH OF THE DESIGN ………………………………………………………………...…..P.3

3. THE DESIGN CREATED……………………………………………………………………………..P.5

4. THE TEST FOR DISTANCE ……………………………………………………………………….P.11

5. THE CONNECTION TO PHYSICS..................................................................P.12

6. CONCLUSION………………………………………………………………………………………...P.14

Page

ABOUT THE MOUSETRAP CAR

ABSTRACTA mousetrap car is a vehicle that is designed to work exclusively with the force from a

mousetrap. Different designs enables the cars to either travel fast or a greater distance. In this

project, the groups in our class had to design and construct a mousetrap that is efficiently built

for great distance. We will see how different designs and variations effect the car and explain

the design we created.

Purpose

This activity enables us to bring out our creative yet logical thinking to construct a mousetrap

car based on the principle of Hooke’s Law. Using our previous knowledge from the chapter we

can research and design a car powered by the spring of a mousetrap.

The power source

The power source of the car is indeed the spring

on the mousetrap car. The spring propels the

hammer, which causes an enormous release of

energy. The hammer is connected to a string

that is wound around the drive the hammer is

connected to a string that is wound around the

drive axle. The string unwinds as the hammer

snaps– making the car roll!

Page

RESEARCH OF THE DESIGNMousetrap car designs over the years have become quite innovative and complex. These cars can be

built in many shapes and sizes. The smaller cars are design to add speeds to the car and long cars are

built for greater distance. Our objective in this case is to build a car for distance. Here are some of the

things we had to consider when we built the car:

The body or frame: A frame is important for a mousetrap car because it provides structural support for

other parts such as wheels, axle and engine. In order for the mousetrap to travel a long distance, a body

with lightweight materials such as wood, cardboard or Styrofoam is ideal.

The wheels: A wheel of mousetrap car is the main component to provide distance or speed in the

testing. The ideal wheels of the mousetrap car should be light weight and aero dynamic, but strong

enough to handle the force exerted from the mousetrap.

The lever: For a greater distance, the lever of the mousetrap car needs to be long, in order for the string

to weave around the axle longer.

The placement of the engine: The mousetrap placement is key for the car to determine its speed or

distance. The farther away the mousetrap is from the back wheel, the greater distance it will run.

Axle: To avoid most friction the axle of the car needs to spin freely. Although, friction cannot be

completely eliminated, it is still important to have a good axle, to ensure maximum efficiency.

DESIGN VARIATIONS

Here we will explore the common design variations, in order for us to get the ideal mousetrap for

distance.

The “4 wheel leaner” Design (left picture)

This design distributes most of its weight

forward, to generate a forward momentum. It

also maximizes stability while in motion.

The standard “4 wheel: design (right picture)

Page

This design imitates the basic design of a 4 wheel car. With this design, stability is really prioritized, while

the motion solely depends on the ability of the axils and the wheel to rotate with as little friction as

possible. (The weight is distributed evenly)

The “3 wheel leaner” design (picture below)

This design maximized the rotation of the

back wheel, in order to cover as much

distance as possible with 1 rotation of the

wheel. It also generates a forward

momentum as the weight is distributed at

the front of the car. However, this design

lacks stability.

Page

THE DESIGN CREATEDWe chose the “4 wheel leaner” mouse trap car

design. The reason is because we wanted to distinct

the designs from the other concepts, and still keeping

its main purpose in mind; to cover as much distance as

possible. With this design, most of the weight is

distributed on the front side. When the car goes into

motion, more forward momentum will be generated.

Inspiration of our design

The primary inspiration for our car was based on a simplistic design of a dragster. The dragster

race care is primarily made for going in a straight line, very quickly. Dragsters that run today use

enormous amounts of power, along with their aerodynamics, and light weight structure they

can travel up to speed of 250 mph. F1 cars were also another factor of our inspiration. We

played out the perfect weight to power ratio, and using these ideas we created our mousetrap

car. Hoping it would travel the distance with no difficultly.

1. Body of the car:

We used a standard wood material, which is usually used on dressers/shelves, that is cut into a

long strip-shape. The reason we did this was to allow a reasonable amount of space for the

other key features of the car, as well as to provide stability (as the mousetraps goes into

motion) while the car and the mousetrap runs simultaneously.

2. Wheels :

Page

a. Front wheel: We used two toy truck’s wheels that is about a quarter of size compared to

CD’s. The reason we chose these wheels is because we want to stabilize the front side of the car

as much as possible (since it affects the steering the most), in

order to steer the car as straight as possible

b. Back wheel: We used 4 CD’s in total, with 2 CD’s connected

parallel with bottle caps for each side. The reason we did this was

in order to minimize weight on the back side of the car, while

maximizing stability (so the CD does not wobble in motion).

3. Mousetrap design/position:

Our actual mousetrap is located at the front side of the car

(behind the front wheel axis). We did this with the intention of

distributing the weight to the front of the car (to generate more

forward momentum as the car is in motion). The design of our

mousetrap includes an extension using a firm rod, connected to

the mousetrap arms, which provides extra leverage in

transferring the potential energy into the motion of the back

wheel (it allows a greater length of string to be attached to the mousetrap from the back wheel

axis.

4. Aerodynamics:

Considering the aerodynamics of our design, we cut the

front of the body of the car into a V shape, in order to

distribute air to the sides of the car (so it does not

become a drag force that opposes the motion of the

car), therefore making our car design, aerodynamic.

Page

DESIGN

DIAGRAMS

Page

THE TEST FOR DISTANCEConsidering all factors of the car such as weight, design, aerodynamics, etc. we hypothesized

that the car should at least run around a distance of 20 m. When we first tested our car,

unofficially, our reached a distance of around 18 m. Although this may not be the ideal distance

we were aiming for, it was still enough to boost our confidence for the official test done by the

teacher.

Reasons why we thought it could run 20 m:

1. The car weighed less than 200 g.

2. The car aerodynamic design should be able to cut the air like a knife through butter.

3. The weight to power ratio was significantly efficient, and it should deliver a good

distance.

4. The front wheel was smaller than the back wheel.

5. Also, when we tested it the first time it ran around 18 m.

The results:

On the day of the final test, we were told to prepare our car by winding it and start from the

first lines. The track was set up with tape being the lines and each with a distance of 5 m apart.

Our goal was to reach the fourth line which was a great distance 20 m. As soon as our turn was

called our car broke down and one of the back wheel completely collapsed because of the

significant amount of force. As we tried gluing it at the last moment, it was fixed but very

unstable as it was not parallel with the other wheel and axle. Anyways when we called down

the second time, we let our go and hoping it would not drift too much. In the end our car went

distance of around 15 meters, but it also had a deviation of around 3 meters.

As we were disappointed in our efforts to save the car, we were kind of pleased, since the car at

least went a good 15 m, with the back off again. That day we learned that we always have

prepare for the worst of disasters, and never lose hope in making something better.

Page

Page

CONNECTION TO PHYSICS (COMMUNICATION PART):ENERGY:

Perhaps the single most important concept to understand in order to build a mousetrap powered vehicle is the concept of energy. Energy is defined as having the ability to do work and work is the displacement of an object that result in something being done. Energy can be classified in a number of ways but most commonly energy is classified as potential and kinetic. The energy that is stored and/or held in readiness is called potential energy (PE). For example, a stretched or compressed spring has the potential to do work. Kinetic energy (KE) is energy of motion or the energy a moving object has.

MAIN FORMULAS

In this project, the motion of the car is the product of an unbalanced force, which is applied by the mousetrap. Use of a long lever arm attaches to the bar of the mousetrap, and uses string twin to the back axle of the car. Then the spring-loaded bar swings down slowly, and drive the axle spins, as well as the rear wheels rotate to the whole car move forward. The main reason to cause it ceases to be the friction. The frictional force exists between two objects, and it resists sliding or rolling of an object over another. The friction between the axle and the holder and even the air to stop the car keeps moving. Reduce the rub between axle and axis help the car keeps moving after the spring runs out. However, the friction is necessary, the wheels cannot push the car to move forward without it, but too large will cause the car stop, too. As the equation of Ff = μFn, the weight of whole car is equal to the normal force, where

Page

W = F × d The formula for work

done by the car,

where F is the force

and d is the distance.

F = -kx

the force [f] of a stretched/compressed spring is equal to the spring

constant [k] times the distance [x] the spring is

stretched/compressed. Force is measured in newtons, the spring

constant in newtons per meters, and distance in meters.

ETotal = PE + KE + W

the total energy of any system is the sum of

the potential energy, the kinetic energy,

work lost to heat and sound, and any work

done to overcome friction. All energy is

measured in joules.

PE = (1/2) × kx2

the potential energy [pe] of a stretched/compressed

spring is equal to one-half the spring constant [k] times

the distance [x] stretched/compressed squared. Potential

energy is measured in joules, the spring constant in

newtons per meter, and the distance in meters.

μ is unchanged, so that less weight provides less friction. Back to the beginning, the mousetrap has stored all the energy in its really heavy spring. The law of conservation of energy describes that the total energy is remaining constant. Energy cannot be either generated or destroyed. So that most of energy contained in the spring transferred to move the car, and some lost. And the earlier lab shows the potential energy stored in the spring is about 0.84 J. And the Hooke’s law says that the force to extend it by some distance, x, is proportional to that distance, which is F=-kx, where k is force constant, therefore more bend the spring is has more force, bend the arm as close to the axle will provide more force to drive the car.

Other Concepts:

Releasing the spring energy slowly, by way of larger drive wheels, has two key advantages. The first advantage is that it prevents slipping of the drive wheel on the ground/floor as the car accelerates. The second advantage is that the car takes longer to gain speed (accelerate) which results in it traveling farther than a car that gains speed faster. To understand this, consider the following energy equation, which equates the stored spring energy to the kinetic energy gained by the car: Uspring = (1/2)mV2, where Uspring is the spring energy, m is the mass of the car, and V is the velocity of the car right after the spring has released all its energy. However, it is worth mentioning that this equation is an approximation, for two reasons: First, it assumes that there are no friction losses. Secondly, it doesn't account for the rotational motion of the wheels. This equation assumes that the mousetrap car is a fully rigid object. But as it turns out, these assumptions don't change the form of the energy equation and therefore don't affect the validity of my next important point.

In the above equation, we see that V is always constant regardless of how fast the car gains speed (keeping everything else the same). It follows that the car travels farther the longer it takes to reach V. After the car reaches V it will coast until it finally stops. But the coasting distance (after V is reached) will be roughly constant, so the biggest influence on distance traveled on a flat surface is how long it takes the car to gain speed.

The dominant forces on the incline are gravity and the spring force, and by conservation of energy, the vertical distance traveled by the car can be approximated by equating the stored spring energy to the gravitational potential energy gained by the car. Mathematically, we can write Uspring = mgh, where g is the acceleration due to gravity, which is 9.8 m/s2 on earth, and h is the vertical distance traveled on the incline. Note that this equation is an approximation because it assumes that there are no friction losses. Interestingly, we see from this equation that the distance traveled up the incline does not depend on the drive wheel diameter. This is true as long as the drive wheels are small enough so that the spring force can turn the wheels throughout the range of motion of the spring (as the car travels up the incline).

Page

CONCLUSIONIn summary, the reason why we designed our mousetrap car that way, is because we wanted a car that

can transfer as much of the potential energy as possible, into kinetic energy, and also to maintain that

kinetic energy, for as far of a distance as possible. With this in mind, we designed a “leaner” car that

transfer elastic potential energy into a rotating motion of the back wheel, allowing the car to be in

motion, and as the car is in motion, “our leaner” design that generates forward momentum, and

distributes airflow to reduce air drag (that will slow it down) allows the car to travel as much distance as

possible.

IN WAYS TO IMPROVE THE

DESIGN:

To maximize the distance traveled on a flat surface, the friction (internal and external) and the weight of the car must be kept as small as possible. Specifically, this means that:

• All the components of the mousetrap car must weigh as little as possible, while being strong enough for use in the car. This can be accomplished by removing unnecessary material, such as by drilling holes in the components such as the frame and wheels.

• The wheels must be rigid and thin to minimize rolling resistance with the floor (or ground). But the drive wheels must additionally provide enough traction so that they don't slip when the car is accelerating.

• The frontal area of the car must be as small as possible to minimize air resistance. Although this will be much less than rolling resistance, every little bit helps.

In conclusion, although our mousetrap did not travel the distance we had expected, and we need to

make some key changes mentioned above, so the car to could run more smother and further. In this lab

we learned many things about energy, conservation and forces applying them to many concept we

Page

learned throughout the course. Overall, this summative was a fun and interesting way to wrap up the

course and it gave everyone an opportunity to experience the reality of being creative and innovative.

Page