Presently, the speed of light in a vacuum is defined to be exactly 299,792,458 m/s (approximately 186,282 miles per second). . An early experiment to measure the speed of light was conducted by Ole Romer, a Danish physicist, in 1676. Using a telescope, Ole observed the motions of Jupiter and one of its moons, Io
The second one because you don't get shocked by plugging in something you can get electricted by putting something thin in the outlet then it will send a shock to your hand
The best option is B) <span>7.0 × 10² newtons.
</span>If Earth attracts a person with a gravitational force of <span><span>7.0 × 10² </span>newtons,
the person attracts Earth with a gravitational force of 7.0 × 10² newtons.</span>
The steel would expand by 4. 8 * 10^-3 cm
<h3>How to determine the linear expansion</h3>
The change in length ΔL is proportional to length L. It is dependent on the temperature, substance, and length.
Using the formula:
ΔL= α LΔT
where ΔL is the change in length L = 10cm
ΔT is the change in temperature = 60° - 20° = 40° C
α is the coefficient of linear expansion = 1.2 x 10^-5 °C
Substitute into the formula
ΔL = 
ΔL = 
cm
Therefore, the steel would expand by 4. 8 * 10^-3 cm
Learn more about linear expansion here:
brainly.com/question/14325928
#SPJ1
