Simple machines
What is the symbol for moment
Nm or Ncm (Newton meters or Newton centimeters
What are the 2 poles?
North and south poles
What is the symbol for current
A (amperes)
What is MgCl₂
Magnesium chloride
Which class lever has a load between the fulcrum and the effort?
Second class levers
What’s the formula for calculating pressure?
P = F/A (pressure equals to force divided by area)
Give 2 examples of magnet types (not shapes)!
Permanent magnet and electromagnet
What is the name of the device that can measure the current of a circuit?
An ammeter
What’s the chemical name of rust?
Iron oxide
Mention at least two types of pulleys!
Fixed pulley / Moveable pulley / Combined pulley
Why do high-heeled shoes exert more pressure than normal shoes?
High-heeled shoes has less surface area than normal shoes
List 3 magnetic elements
Iron, Nickel Cobalt
Mention the formula of Ohm's Law
V = IR (voltage equals to current multiplied by resistance)
What’s the difference between physical and chemical change?
Physical change is a change of state, while chemical change is whenever a new substance is formed
Give 1 example of a second-class lever!
Nut crackers / Wheelbarrows / Doors / Bottle openers
To which direction is the pressure in a liquid acting?
All directions
How can we increase the strength of an electromagnet?
Increasing the number of coils / increasing the size of current flow
What’s the effect on the voltage across a lamp in a series circuit when an identical lamp is added?
Decreased voltage
What are the elements present in H₃PO₄?
Hydrogen, phosphorus, oxygen
Name all 6 simple machines
Inclined plane, Screw, Wedge, Lever, Pulleys, Wheel and axle
Calculate the pressure exerted by an obese guy weighing 150 kg using boots with a total surface area of 25 m2. (Use 1kg= 10N)
60 Pa or 60 N/m2
What are 2 advantages of electromagnets compared to permanent magnets?
The magnetic field in electromagnet can be switched on/off and the direction of the flow can be changed
What is the difference between a normal resistor and a variable resistor?
Variable resistor can change resistance, while normal resistor have a fixed resistance
List at least 4 ways to identify a chemical change
Color change / Gas given off / Heat produced / pH change / Precipitate formed