A. A child rubs a balloon
Gravitational potential energy = mass × gravity × height
Ep = (4)(9.81)(3)
Energy = 117.72 Joules
= 1.2x10^2 Joules
A. The formula for mean free time is:
t = V/(4π√2 r²vN)
where
N = 1×10¹⁶ molecules (per m³)
V = 1 m³
r = 111×10⁻⁷m (atomic radius of silicon)
Let's solve for v first:
v = √(3RT/M) = √(3(8.314 m³·Pa/mol·K)(25 + 273 K)/28.1 g/mol Si)
v = 16.26 m/s
t = (1 m³)/(4π√2 (111×10⁻⁷m)²(16.26 m/s)(1×10¹⁶ molecules))
<em>t = 2.81×10⁻9 s</em>
<em>Pure silicon has a high resistivity relative to copper because copper is a conductor, while silicon is a semi-conductor. </em>
Answer:
86.6, 45°
Explanation:
The diagram explains better.
Using vector component method:
We find the x and y components of the vectors :
For the first:
A = -50cos(0)i + 50sin(0)j
A = -50i
For the second:
B = -50cos(60)i + 50sin(60)j
B = -25i + 43.3j
The resultant vector is :
R = A + B
R = -50i - 25i + 43.3j
R = -75i + 43.3j
The magnitude is:
R = [(-75)² + (43.3)²]^½
R = 86.6m
The angle is
tanθ = (50/50) = 1
θ = 45°