Topic 1
Name the three parts of a lever
Fulcrum, Load and Effort
Name the complex system that is a combination of fixed and movable pulleys.
Block and Tackle
State Pascal’s Law
Pascal's Law states that pressure is transmitted unchanged in all directions throughout the fluid.
What is a complex machine?
Several simple machines working together in a system.
Explain how science has been used to improve the vehicles that we drive today.
Alternative fuel sources are being used.
More compact.
Name and give an example of each type of lever.
Answers will vary.
Class 1- Teeter totter, scissors
Class 2- Wheelbarrow
Class 3-Hockey stick, arm
Calculate the speed ratio if the front sprocket on a bike chain has 45 teeth and the follower sprocket has 15 teeth.
3
Real machines are always less than 100% efficient. Explain.
Every time a real machine does work, some energy is lost to friction.
Explain two differences between hydraulic systems and pneumatic systems.
Hydraulics use liquids and pneumatics use gases (typically air)
Pneumatics allow air to pass through the system where hydraulics are a closed system.
Describe mass production. What changes did this bring in our society?
Mass production is the large production of a standardized item.
It brought people from rural areas into urbanized areas.
How much work must you do to lift an elephant weighing 60 000N up 1.5m onto the back of a truck?
Work = Force x Distance
Work = 60 000N x 1.5 m
Work = 90 000 J
Describe 2 benefits of a wheel and axle device.
Mechanical Advantage
Speed Advantage
Explain how friction can make machines useful.
Friction keeps objects from sleeping, for example, bike tires and the ground, shoes and the ground.
Give four examples of pneumatic systems.
Examples will vary.
Sand blaster
Jack Hammer
Staple Gun
Air Cast
Name and describe each process the internal combustion engine goes through.
Intake Stroke - draws in fuel
Compression stroke - compresses fuel
Power Stroke - ignite the mixture
Exhaust Stroke - pushes out waste products
A crafty coyote is trying to use a catapult to launch a heavy rock. The rock, with a mass of 1000 kg, sits on one end of a plank. The coyote figures that if he jumps on the other end of the plank, his 25 kg mass will be enough to launch the rock into the air.
Calculate the mechanical advantage the catapult must have for the coyote's plan towork.
Mechanical Advantage = Load Force/Effort Force
Mechanical Advantage = 1000 kg / 25 kg
Mechanical Advantage = 40
Describe the differences between a fixed and movable pulley. Give examples of
each.
Fixed Pulley - attached to something that does not move. Ex. flag pole
Movable Pulley - attached to something else, often by a rope that goes around the pulley itself. Ex. End of crane ropes
Why does a hydraulic lift provide a mechanical advantage?
A hydraulic lift uses a liquid to produce a large force on a load when a small effort force is exerted on the liquid.
What are the simple machines used in a backhoe?
Hydraulics
Class 1 Lever
Class 2 Lever
What questions must you ask yourself about the machine you want to build?
What is it you want the technology to do?
Define ergonomics. Explain what can happen if you do not use ergonomic products.
Ergonomics is the science of designing machines to suit people. Carpal Tunnel
Syndrome is numbness and pain in the thumb and first three fingers.
If you wanted a winch to have a mechanical advantage of 4 and the radius of the axle was 5 cm, how long would the handle have to be?
20 cm
The work done by a ramp is 1430 J. The work done by the effort force is 1650 J. What is the efficiency of the ramp?
86.7 %
Give an example of a hydraulic system in your body. What makes it a hydraulic system?
The circulatory system is a hydraulic system because it is a closed system that transports blood around your body.
Which of the following is true:
Technology changes society
OR
Society changes technology?
Answers will vary!