Give an explanation
Explain the scientific definition of work.
Ans = Applying force on an object and making the object move
What is the formula for calculating the gear ratio
Ans: Driven/driver
What are three examples of types of energy used by machines?
Ans: Electrical, Heat, Solar, light, kinetic, chemical, nuclear… etc.
What are 3 examples of simple machines?
Ans: Lever, Inclined plane, Pulley, Wheel & Axle, Wedge, Screw
John pulled the pulley with 50 N and on the other side of the pulley, a truck was connected, lifting 1 m. Calculate the Mechanical advantage:
Ans: 1/50 = 0.02, the Mechanical advantage in this case is 0.02:1
Explain the Speed ratio in simple words:
Ans: It is another way of measuring how speed of an object is affected by machine
What are complex machines in simple words?
Ans: A machine system with many simple machines
What is a rube goldberg machine?
Ans: An overly complicated machine to achieve a straightforward task
What is an example of 2 items made for similar purposes but at different times? (eg. Typewriter, Keyboard)
Ans: Telephones, Smartphones, etc.
John pushed the truck 8 meters up an inclined plane and the truck lifted 2 meters, calculate the speed ratio:
8/2=4, the speed ratio of this situation is 4:1
Explain Mechanical advantage in simple words:
Ans: the amount of force a machine can multiply
Theoretically, a machine is 70% efficient, is the real efficiency smaller, bigger, or the same? Why?
Ans: The real efficiency of this machine is smaller than the theory because of the existence of fiction, which will make the machine less efficient.
What is the difference between pneumatic and hydraulic?
Ans: Hydraulic machines use liquid, pneumatic uses air
What is the definition of a mechanical device?
Ans: A mechanism designed to make work easier
Joe pushed with 80N and the car moved 9 meters, what is the work in this situation?
80 * 9 = 720J
How does a hydraulic system work?
Ans: Liquid Is compressed in a tight container to push objects
What is a subsystem?
Ans: It is a part of a whole machine system to perform tasks
What was Rube Goldberg’s Profession?
Ans: Cartoonist
What fixed point does the rigid bar rotate around in a lever?
Ans: The fulcrum
On a bike, the second front gear has 24 teeth and the back gear has 24 teeth, Calculate the gear ratio
Ans: 24/24 = 1, the gear ratio is 1:1
What were machines first powered by?
Ans: it was powered by humans and animals
What is the main difference between TV 200 years ago and now?
Ans: There weren’t TVs 200 years ago
What is the difference between potential and kinetic energy?
Ans: Potential is energy stored up, kinetic is energy in use
Are you a machine?
Ans: You’re hilarious if you said yes because we aren’t
Bob is using a lever to move a table, he’s pushing with 20N but the table is 80N, with this amount of force he pushed 8 m, but the table moved 1m up. What is the theoretical efficiency of the lever?
MA = 80/20 = 4N SR = 8/1=8 EFF= 4/8 * 100 = 50%