Answer:
Petametres; 41 Pm
Explanation:
A measurement should use units that give a number between 0.1 and 1000.
The measure that astronomers use is the light year — the distance that light travels in one year.
In those units, the distance is 4.3 light years.
We can calculate the distance in SI units.

In SI, we should measure the distance in petametres (1 Pm = 10¹⁵ m)
Thus, the distance to the nearest star is 41 Pm.
Here it is. I used the surface charge density σ as q/Area, and then wrote it out in terms of q at the end
Answer:
Exercise 1;
The centripetal acceleration is approximately 94.52 m/s²
Explanation:
1) The given parameters are;
The diameter of the circle = 8 cm = 0.08 m
The radius of the circle = Diameter/2 = 0.08/2 = 0.04 m
The speed of motion = 7 km/h = 1.944444 m/s
The centripetal acceleration = v²/r = 1.944444²/0.04 ≈ 94.52 m/s²
The centripetal acceleration ≈ 94.52 m/s²
<h2>
The velocity of the boat relative to an observer standing on either bank = u = 18 
</h2>
Explanation:
Let speed of the boat in still water = u 
speed of the river water = v 
Relative speed of the boat in the water against the river flow is given by
Upstream speed = u - v ------- (1)
⇒ u - v = 12
------ (2)
Given that speed of the water = 6 
Now velocity of the boat is given From equation (2)
⇒ u = 12 + v
Put the value of v = 6 , we get
⇒ u = 12 + 6
⇒ u = 18
therefore , the velocity of the boat relative to an observer standing on either bank = u = 18 
Answer:
Before: 0 m/s
After: -4 m/s
Explanation:
Before: Since you and your beau started at rest, your beau initial velocity is 0 m/s.
After: Since we have to conserve momentum,
momentum before push = momentum after push.
The momentum before push = 0 (since you and your beau are at rest)
momentum after push = m₁v₁ + m₂v₂ were m₁ = your mass = 60 kg, v₁ = your velocity after push = 3 m/s, m₂ = beau's mass = 45 kg and v₂ = beau's velocity.
So, m₁v₁ + m₂v₂ = 0
m₁v₁ = -m₂v₂
v₂ = -m₁v₁/m₂ = -60 kg × 3 m/s ÷ 45 kg = -4 m/s
So beau moves with a velocity of 4 m/s in the opposite direction