Answer:
c) True. factor four
Explanation:
The energy density of an electromagnetic wave is given by
u = ½ ε₀ E² = B² / 2μ₀
Where ε₀ is the dielectric constant and μ₀ the magnetic permittivity.
Let's apply this equation to the present case
If we double the electro field
E ’= 2 E₀
u’= ½ ε₀ (2E₀)²
u’= ½ ε₀ Eo² 4
u’= 4 u₀
Therefore the energy is multiplied by four
Let's check the answers
a) False
b) False
c) True
d) False
e) False
Answer:
Force must be applied to m₁ to move the group of rocks from the road at 0.250 m/s² = 436 N
Explanation:
Total force required = Mass x Acceleration,
F = ma
Here we need to consider the system as combine, total mass need to be considered.
Total mass, a = m₁+m₂+m₃ = 584 + 838 + 322 = 1744 kg
We need to accelerate the group of rocks from the road at 0.250 m/s²
That is acceleration, a = 0.250 m/s²
Force required, F = ma = 1744 x 0.25 = 436 N
Force must be applied to m₁ to move the group of rocks from the road at 0.250 m/s² = 436 N
To throw an object into the space you need to throw it with the escape velocity of the earth which is 11.2 km/sec. therefore if you can throw an object with the speed of 11.2 km/sec it will leave the earth atmosphere and will reach to the space.
