Answer:
Springs are made of a variety of materials including copper and various forms of steel. The most common is high carbon steel as it is cheap, easy to work and a couple of other important properties.
Copper springs exist as well, but copper is more expensive than steel. However, in an environment where corrosion resistance is important, copper springs are a good alternative.
Explanation:
Answer:
A. True
Explanation:
When a stone is thrown straight-up, it has an initial velocity which decreases gradually as the stone move to maximum height due to constant acceleration due to gravity acting downward on the stone, at the maximum height the final velocity of the stone is zero. As the stone descends the velocity starts to increase and becomes maximum before it hits the ground.
Height of the motion is given by;

g is acceleration due to gravity which is constant
H is height traveled
u is the speed of throw, which determines the value of height traveled.
Therefore, when the stone is caught at the same height from which it was thrown in the absence of air resistance, the speed of the stone when thrown will be equal to the speed when caught.
Answer:
a) v = 141.9 m/s
b) v = 317.4 miles/h
Explanation:
a) How fast was he moving in meters per second?

Hence, the jet ski is moving at 141.9 meters per second.
b) How fast was he moving in miles per hour?
Therefore, the jet ski is moving at 317.4 miles per hour.
I hope it helps you!
Answer:
Micro and radio waves.
Lower energy.
Gamma rays.
Explanation:
The electromagnetic spectrum is the range of frequencies of electromagnetic radiation and their respective wavelengths.
Ionising radiation os defined as the energy required of photons of a wave to ionize atoms, causing chemical reactions.
The energy of the wave depends on both the amplitude and the frequency. If the energy of each wavelength is a discrete packet of energy, a high-frequency wave will deliver more of these packets per unit time than a low-frequency wave. In summary, the longer the wavelength, the lower the energy to ionise.
The velocity of a wave is directly proportional to the frequency of that wave.
c = f * lambda
Where,
c = velocity of the wave
f = frequency of the wave = 1/time
Lambda = wavelength.
From the above expression, the longer the wavelength, lambda the shorter the frequency.
Examples of waves with longer wavelengths are, micro and radio waves, while radiations with shorter wavelengths like gamma rays.