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AIM: How do we apply concepts of momentum, impulse, and force to design a system which reduces the collision force of an egg dropped from a height.
AIM: How do we apply concepts of momentum, impulse, and force to design a system which reduces the collision force of an egg dropped from a height.
Goal:
Goal:
Students will design and build a landing pad that will protect an egg from cracking when dropped from a at least 1 meter and no more than 2 meters , using only 10 sheets of paper and 1 meter of tape, while staying within a budget of resources.
Objectives Students will:
» describe a collision in terms of changing momentum, impulse, impact force, and impact time.
» observe and document the effectiveness of safety devices such as seat belts and airbags by designing, building, testing, and evaluating a safety device to protect an egg during a collision.
Students will be in a group of 3-4, and will need to document their design process as part of the project
Background Information
When Newton described the relationship between force and inertia, he spoke in terms of two other physics concepts: momentum and impulse. Newton defined momentum as the product of an object’s mass and velocity (see “Momentum Bashing”). Newton defined impulse as the quantity needed to change an object’s momentum.
To change an object’s momentum, the mass of the object, the velocity of the object, or both have to change. If the velocity of an object increases (accelerates) while its mass remains constant, its momentum also increases. In his second law, Newton said that in order to accelerate (or decelerate) a mass, a force must be applied.
This notion is often expressed using the equation F=ma.
A force “F” is needed to move a mass “m” with an acceleration of “a.” The greater the force applied to an object, the greater its acceleration (i.e., the greater its change in velocity) and the greater its change in momentum.
Scientists and engineers regularly use and apply the laws of physics in order to design vehicle structures and added features in order to minimize the physical damage to vehicles and injury to vehicle occupants in the event of a collision.
This experiment will simulate how to minimize the risk of injury to delicate structures and organs in a body.
Background Information (continued)
In addition to changing momentum by changing the amount of force applied to a moving object, changing the amount of time a force acts on an object also changes momentum. Applying the brakes briefly to a moving vehicle slightly reduces its momentum. Applying the same braking force over an extended period of time greatly reduces the vehicle’s momentum.
Similarly, slamming on the brakes of a moving vehicle for a short period of time reduces the vehicle’s momentum much more than lightly tapping on the brakes for that same period of time. The product of a force and the time it is applied to an object is called impulse. Impulse is mathematically represented as impulse = force x time interval.
The greater the impulse exerted on a moving object, the greater its change in momentum. The amount of damage/injury that occurs in a collision is directly related to the impulse of a collision. Lengthening the time during which a “stopping” force is applied to a vehicle (and its occupants) in a collision reduces the final “net” force acting on the vehicle and its occupants when they finally come to a stop. Seat belts and airbags are examples of two major safety features that apply these laws of physics to reduce injuries in collisions. ;
Both features help lengthen the amount of time between when the stopping force is first applied to a vehicle (e.g., crashing a car head-on into a wall) and when the occupants inside the car actually collide with the dashboard, steering wheel, or other vehicle structure.
Next Generation Science Standards* Motion and Stability: Forces and Interactions » HS-PS2-1 HS-PS2-3, MS-PS2-2, 4-PS3-1 Engineering Design » HS-ETS1-2, MS-ETS1-1, MS-ETS1-2, MS-ETS1-3, 3-5-ETS1-1, 3-5-ETS1-2, 3-5ETS1-3
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