The ammeter is a device used to measure the amount of current flowing in a system. This is done by allowing the current in the system to flow through the device.
Another device used in electrical systems is the voltmeter. The voltmeter measures the potential
difference between two points of the electrical system by diverting the electrical current away from
the device to the rest of the circuit.
The relationship between potential difference (V), current (I) and resistance (R) are as follows:
V = IR
Which of the following properties of ammeters and voltmeters are compatible with their functions?Deselect Answer
Newton's first law states that an object at rest will stay at rest, and an object in motion will stay in motion unless acted on by a net external force. Mathematically, this is equivalent to say that if the net force acting on an object is zero, then the velocity of the object is constant. When the bus starts to move abruptly, passengers lean back. In case of sudden braking, on the contrary, they lean forward.
This observation seems to contradict Newton's first law, because outside forces do not act on the
people. Which of the following is the correct statement regarding this observation?Deselect Answer
A hydraulic jack lift can be used to increase the force of an operator due to the difference in area of the pistons in the cylinders. The diagram below shows a modified hydraulic jack lift that has a cone shaped piston on the lifting edge.
What utility can this modification provide for the hydraulic jack?Deselect Answer