Grade 4 - Machines and their Mechanisms
List an example of something that uses a pulley mechanism
Crane, Well, Elevator etc.
List an example of protective equipment that humans use to keep us safe from the impact of forces.
Answers may vary. (eg. a helmet keeps our heads from being compressed)
List one property of air (there are more than one)
Air has mass, takes up space, exerts pressure, temperature, it can be compressed, its affected by altitude
List an example of something that uses a gear mechanism
Car, Clock, Bike etc.
Which of the following uses a pulley?
a) Bicycle
b) Clock
c) Water Well
d) Motorcycle
C
What is the difference between a simple machine and 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 difference between a static and dynamic load?
Dynamic loads are subject to change. Static loads stay the same.
What is flight?
Flight is the action or process of flying through the air
Identify a positive and negative way that machines can impact the environment
Answers will vary.
Eg. A car produces gases that can affect the environment.
A train allows many people to travel to similar locations all at once, reducing greenhouse gases
Gears are used to change what three things?
a) Inputs, outputs and force
b)Pulleys, crowns and torque
c)Acceleration, braking and direction
d)Speed, direction and torque
D
Complete both blanks.
__________ motion is movement in a circular path.
__________ motion is movement that occurs in a straight line.
Rotary, linear
What is the difference between an internal and external force? Give an example for each.
Internal forces are forces that occur within a structure (eg. tension, compression, torsion and shear)
External forces are caused by external agents in a structure. An example could be wind or snow on a building.
What is Bernoulli's Principle?
The faster air flows, the less pressure it has.
(eg. blowing air creates lift rather than still air)
Fill in all the blanks.
_________ bridges have an assembly of triangles for extra support.
________ bridges are held up by ropes attached to tall structures.
Truss, Suspension
What is an example of a non-contact force?
a) A baseball player hits a baseball with a bat
b) A construction worker uses a shovel to dig a hole
c) A skydiver parachutes out of a plane toward the ground
d) An author types a book on a laptop
C
Complete all blanks.
_______ is a measure of rotational force.
_______ machines are made of two or more simple machines.
_______ are systems in a machine that can modify a motion
Torque, Complex, Mechanisms
Fill in all the blanks.
_______ bridges are the simplest type of bridge. They have a horizontal beam and a deck.
_________ bridges have a semicircle shape to provide support
Beam, Arch
Fill in all the blanks
________ is the force that acts against weight cause by air moving over and under the wings
_______ is the force that acts against thrust caused by the resistance of air
Lift, Drag
List a benefit and a consequence of aviation technology
Answers may vary.
Eg. a benefit is that with aviation, we are able to travel the world much easier and faster
A consequence of aviation is the pollution most planes and international travel produce
Which is an example of an internal force on a bridge?
a) Pedestrians walking on the bridge
b) Tension on the bridge cables
c) Vehicles driving along the bridge
d) Snow collecting on the bridge
B
If the first gear is turning clockwise, the second gear will turn __________.
The fastest gear is always the _________ gear.
Counter-clockwise
Smaller
What is the direction and point of application of a force, like a box being pushed?
The direction is the course along which the force is moving (eg. the direction the box is being pushed)
The point of application is the exact location at which a force is applied to a body (eg. where the hand is on the box)
Fill in all the blanks
_______ is the force that moves an object forward, which can be provided by muscles, engines or gravity.
_______ is the force that pulls everything down toward the earth due to gravity
_______ is the study of how air moves around things
Thrust, Weight, Aerodynamics
Use the properties of air to explain how a hot air balloon is able to fly
A hot air balloon uses a burner to heat up the air inside the balloon. This burner creates a flame that is located directly below the bottom of the hot air balloon. The hot air balloon will rise once the air under the balloon gets hot enough. The pilot of the balloon is able to adjust the altitude of the hot air balloon by controlling the flame.
Which of the following is NOT one of Newton's principles?
a) A body continues to be at rest or in motion unless an external force is applied to it.
b) The greater the mass(weight) of a body, the greater the force needed to accelerate it
c) For every action, there is an equal and opposite reaction.
d) The greater the drag, the less force is required
D