Types of Forces
This force pulls something tight like a rope.
Tension
what is the simplest type of bridge, often supported at both ends.
Beam bridge
What shape is used in many structures to hold them strong?
triangles
What is the name of the world-famous tower in France?
The Eiffel Tower
You’re building a tower and it keeps tipping over. What should you try? WHY?
Make the base wider/ add weight to the bottom to lower the center of gravity.
This force can tear objects in opposite directions.
shear
This bridge uses a curve to support the weight from above
Arch bridge
Should the center of gravity in a stable structure be higher or lower than the middle?
lower
This bridge in San Francisco is an example of a suspension bridge.
Golden Gate Bridge
Your roller coaster model snaps when twisted. What force broke it?
torsion
This force pulls objects towards the earth.
gravity
Why are truss bridges so strong?
Because triangles distribute weight evenly, making them the strongest shape
How can you make a tall tower more stable?
Make the base wider to lower the center of gravity
What kind of bridge is the Brooklyn bridge?
Suspension bridge
Your bridge is bending too much in the middle. What force is acting on it and how can you fix it?
Compression - add support beams or trusses
Explain the difference between an external force and an internal force.
An external force happens when force is applied to the outside of an object/ structure and an internal force happens inside a structure/object
Give two examples of a static load and two examples of a dynamic load acting on a bridge.
Static: snow sitting on the bridge, cars sitting in traffic, gravity
Dynamic: cars driving, people walking
What is the center of gravity?
The point in a structure or person where the weight is evenly balanced
What aspects of the CN tower make it a stable structure?
Its wide base and lower center of gravity
You're designing a rescue structure for windy areas. What is something you should consider to keep it stable and safe?
Low height
What two forces act on a swing when a person is sitting on it.
Weight and tension
What kind of force is holding up the cables of a suspension bridge?
Tension
Why are domes used as structures for buildings like stadiums?
They are strong shapes that spread out the force, and are low to the ground
In cold areas, buildings often have slanted roofs. Why?
To let snow slide off, reducing the compression force from heavy snow
Your tower keeps leaning to one side. What force might be pulling it down?
gravity