Answer:
true
Explanation:
Friction occurs because no surface is perfectly smooth. Rougher surfaces have more friction between them. Heavier objects also have more friction because they press together with greater force. Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy.
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:
The frequency of the wheel is the number of revolutions per second:
f= \frac{N_{rev}}{t}= \frac{10}{1 s}=10 Hz
And now we can calculate the angular speed, which is given by:
\omega = 2 \pi f=2 \pi (10 Hz)=62.8 rad/s in the clockwise direction.
Explanation: