Grade 4
Explain what a simple machine is and how it compares to a complex machine?
A simple machine is a basic tool that helps apply force and do work. A complex machine is made up of two or more simple machines.
What is the definition of rotary?
Rotary: motion is movement in a circular path.
What is the difference between a static and dynamic load?
Dynamic loads are subject to change. Static loads stay the same.
What is a truss bridge?
Truss: a bridge that uses triangles for extra support.
A pulley because when you pull the cord, it raises the blinds.
List at least 3 things with a pulley mechanism
Crane, well, elevator, flagpole, curtain, etc.
What is the definition of linear?
Linear: motion is movement that occurs in a straight line.
List three examples of protective equipment that keep humans safe from the impact of forces, and explain the force they protect against?
Helmet, knee pads, mouth guard, steel toe boots, seat belt, life jacket, harness, goggles, etc.
What is a beam bridge?
Beam: the simplest type of bridges. They have a horizontal beam and a deck.
Name 3 natural disasters we learned about and 1 way that humans have developed structures to prevent damages in the future.
Many answers.
List at least 3 things with a gear mechanism?
Car, clock, bicycle, wind up toys, etc.
What is the definition of a complex machine?
Complex: machines are made of two or more simple machines.
What is the difference between an internal and external force?
Internal forces are forces that occur within a structure (e.g. tension, torsion, shear, and compression). External forces are caused by external agents in a structure. An example of this is the wind or snow affecting a structure, or occupants in a building.
What is an arch bridge?
Arch: a bridge that has a semicircular shape to provide support.
Explain the input and output components to a bicycle.
You push the pedals which moves the gears as your input force and the wheels spin to move the bike as the output force.
What is the definition of torque?
Torque: is a measure of rotational force.
What is the definition of a mechanism?
Mechanisms: are systems in a machine that can modify a motion
List the 4 internal forces?
tension, torsion, shear, and compression
What is a suspension bridge?
Suspension: a bridge that is held up by ropes attached to tall structures.
They built their houses on stilts and piers and they have created water systems.
Explain how machines can have a positive and negative impact on the environment?
Machines can make the world more accessible for people and make it easier for us to do our jobs. People can use mechanisms like a wheel chair or elevator to get around easier. Vehicles can also cause a lot of pollution and using big machines for building and construction can impact our environment. (You can come up with other examples as well).
What are the 3 things that gears do?
Gears are used to change the speed, direction, and torque of a force.
What are the 4 types of bridges?
Truss, Beam, Arch, Suspension
Contact because you are touching the door.
Define these words: Direction, Point of Application, Magnitude.
Direction: the course along which a force is moving (which direction it is moving in).
Point of Application: the exact location at which a force is applied to a body (ex. where your hand is touching the box you are pushing).
Magnitude: is the measure of the intensity of a force