SIMPLE MACHINES

VOCABULARY

Simple Machine – a machine that does work with only one movement of that machine.

Ideal Mechanical Advantage – the term that is used to describe the amount of force that is utilized internally by some sort of mechanical device; the ideal mechanical advantage (IMA) for any machine can be calculated by dividing the input distance by the output distance; IMA = length of input arm (Lin)/length of output arm (Lout)

LEVERS

Lever – an arm that pivots (or turns) against a fulcrum (or point).

3 Orders http://www.enchantedlearning.com/physics/machines/L

evers.shtml

CATAPULT ENGINEERING PROCESS Design Catapults and make a drawing using graphing paper

Specifications Sheet Average Speed of Projectile Force of Projectile

LEVER IMA PRACTICE

John uses a lever to lift a weight of 5 N. The input distance (where the input force is applied) is 50 cm. The output distance (where the output force is applied) is 5 cm. What is the ideal mechanical advantage of the lever? IMA = input distance/output distance

CATAPULT CONSTRUCTION

10 Popsicle sticks 1 plastic spoon 10 rubber bands 12 inches of tape

MARSHMALLOW LAUNCHING Obtain the mass of the marshmallow Set up your catapult 2 meters from the target Record the time it takes your marshmallow to reach the target 3 trials

CALCULATIONS!!!

With how many Newtons of force did the Marshmallow hit the target? F = ma

Newton’s Second Law – the acceleration of an object is directly proportional to the unbalanced force acting on it and inversely proportional to the object’s mass. The direction of the acceleration is the same as the direction of the unbalanced force.

MASS V. WEIGHT

Mass – the amount of matter in an object; unit: kg

Weight – the vertical, downward force exerted on a mass as a result of gravity; unit: N

CALCULATIONS!!!

We need acceleration! Acceleration – the change in velocity per unit time; a

= Δv/Δt; unit: m/s/s GRAPH YOUR RESULTS

CALCULATIONS!!!

We need the change in velocity! Speed – the distance traveled divided by the time

elapsed; speed is a scalar quantity, it has no direction v = Δd/Δt; unit: m/s

Velocity – the speed in a given direction; displacement divided by the time interval; v = Δd/Δt; unit: m/s Use the time that it took your marshmallow to travel from

the catapult to the target GRAPH YOUR RESULTS

VECTOR VS. SCALAR

Vector – a quantity that has both magnitude (size/amount) and direction

Scalar – a quantity that has magnitude (size/amount) but no direction

PROJECTILE DISCUSSION

Projectile – an object traveling through the air or other medium with no power source of its own

Shape of the path of the projectile? Parabola – a plane curve; the shape of a projectile Gravitational force – 9.8 m/s/s

In what direction would it travel if there was no gravity? Newton’s First Law – in the absence of an unbalanced

force, an object at rest remains at rest, and an object in motion remains in motion with constant speed in a straight-line path

Inertia – the natural tendency of an object to remain at rest or to remain moving with constant speed in a straight line

CALCULATIONS!!!

With how many Newtons of force did the Marshmallow hit the target? F = ma

With how many Newtons of force did the target strike back? Newton’s Third Law – forces come in pairs; the force

of object A on object B is equal in strength and opposite in direction to the force of oject B on object A

THE OTHER SIMPLE MACHINES SMART BOARD

1. Simple Machine

2. Lever3. Vector4. Scalar5. Parabola

6. Mass7. Acceleratio

n8. Speed9. Velocity10.Projectile

11.Newton’s First Law

12.Newton’s Second Law

13.Newton’s Third Law

14.Inertia

BONUS QUESTION (EDMODO CODE: B7Q5Z8) John Deere was hunting with his new crossbow. His crossbow was equipped to shoot bolts, or arrows, that have a mass of 0.50 kg. He spotted a turkey that was about 35.00 m away and quickly set up and shot down the turkey. He estimated that the bolt reached the turkey in about 2.00 seconds. With how much force did the bolt hit the turkey? HINTS

F = ma a = Δv/Δt

v = Δd/Δt