Bernoulli principle
According to Bernoulli's principle, this faster moving air on the top has a lower pressure than the non-moving air on the bottom. With a greater pressure on the bottom of the paper there is also a greater force pushing up.
A tachometer measures, for example it measures the MPH(Miles Per Hour) in a car. So like it measures your speed, so you could be going 100 MPH.
Answer:
The wheelbarrow's wheel and axle help the wheelbarrow to move without friction thus making it easier to push or pull. That's why it will be easier to lift a load in wheel barrow of the load is transferred towards the wheel.
The Electromagnetic spectrum.