Answer:
Explanation:
A magnet has a magnetic field around it which originates at the north pole and enters through the south pole.
In a magnet, like poles will repel each other and unlike poles will attract.
- The north pole of one magnet will repel another north pole of another magnet.
- North pole of one magnet will attract the south pole of another magnet.
- This is the law of attraction and repulsion of magnet.
Answer:
B.
Venus is the same size and density.
Explanation:
It is becuase venus has the same size and density as earth
Answer:
3.45×10⁻⁴mm (or 0.000345mm)
Explanation:
Use a method called dimensional analysis here. It involves a chain of conversions, so we'll need some conversions to work with.
- 1nm = 1×10⁻⁹m
- 1mm = 1×10⁻³m
- 345nm; which is given
If you knew the conversion from nanometers to millimeters then you could just do it in one step. But I don't, so I won't. Anyways, you put the conversions into fraction form like so:
And then orient them in a way where multiplying the two (or more in other instances) gives you the units you want. In this cas it's millimeters so you'll have:
(345nm)•(1×10⁻⁹m/1nm)•(1mm/1×10⁻³m)
Notice how all the units reduce except for mm. From here you just multiply across and should get 345×10⁻⁶mm which simplifies to 3.45×10⁻⁴mm.
5.4 x 1014Hz
wavelength x frequency = the speed of light
Answer:
Explanation:
radius of cylinder r₁ = .02 m
radius of safety valve r₂ = .0075 m
force exerted by spring on safety valve = 950 x .0085 = 8.075 N .
Force required on piston of cylinder = F
Applying Pascal's law
8.075 / 3.14 x .0075² = F / 3.14 x .02²
F = 8.075 x .02² / .0075²
= 8.075 x 7.111
= 57.42 N .
