D&T Quiz 5

What is NOT true about Mechanical Control Systems?

• Open-looped control system has no feedback

• Example of open-looped control system is water tap

• Closed-looped control system has no feedback.

• Example of closed-looped control system is water cistern for flushing

The block diagram shows a closed-looped Mechanical System. Fill in the blank for (i)______________, (ii)____________, (iii)___________ and (iv)_____________

Which is not the correct movement made by the following products

• The bicycle pedal makes a rotary or circular motion to drive the rear wheel

• The pendulum clock makes oscillating movement

• The glue stick move upward in reciprocating movement when the knob is turned

• The saw blade on the scroll saw makes reciprocating motion when cutting

Which is true of functions of mechanism? (You may choose more than one answer)

• Conversion of motion from rotary to linear like glue stick

• Transmit a movement at one point to another like bicycle brake

• Control motion by changing the speed like clock

• Control the amount of force like the car jack

• Control the direction of movement like the bevel gear

Example/s of mechanism that can control motion are (You may choose more than one answer)

• Lever and linkages

• Gears, Rack and Pinions

• Pulleys

• Cams

• Spring

List the truth about Level. (You may choose more than 1 answers)

• positions of lever are fulcrum (pivot), effort and load

• the further the effort is from the fulcrum, the lesser the effort needed to lift the load

• third class lever requires that effort be applied in between fulcrum and load

• Example of second class lever is nutcracker

• Example of first class lever is ice tongs

There are two types of pulleys.

1. _____________ pulley system and 2. _______________pulley system

What is NOT true about pulley system?

• pulley is used to transmit motion

• pulley is used to convert motion

• compound pulley system can reduce the amount of effort to lift a load

• simple pulley system makes no difference to the effort when lifting a load

In mechanism, cam

• is a type of device that take pictures

• consists of gears and springs

• a specially designed and shaped piece of material that rotates, causing a lever or rod to move

• may shaped like pear, eccentric circle or snail

• and follower can converts circular movement to a kind of oscillatory motion

Which is NOT true of gears

• gear train is made of several spur gears

• idler gears makes driver and driven gear move in the same direction

• idler gear is often placed between the driven and driver gear

• When two spur gears of different sizes rotate, they turn in opposite directions

• when two spur gears turn, the small gear turn slower than the larger gear