During the daytime, I have mostly line symmetry.
During the night, I often have almost spherical symmetry.
Answer:
d = 142.5 m
Explanation:
This is a vector exercise. Let's calculate how much the boat travels in the 40s
d₀ = 
t
d₀ = 0.75 40
d₀ = 30 m
Let's write the kinematic equations
Boat
x = d₀ + t
x = 0 + 
t
At the meeting point the coordinate is the same for both
d₀ + t = t
t ( - ) = d₀
t = d₀ / ( - )
The two go in the same direction therefore the speeds have the same sign
t = 30 / (0.95-0.775)
t = 150 s
The distance traveled by man is
d = t
d = 0.95 150
d = 142.5 m
Answer:
3.8 × 10 ⁻¹⁴ m
Explanation:
The alpha particle will be deflected when its kinetic energy is equal to the potential energy
Charge of the alpha particle q₁= 2 × 1.6 × 10⁻¹⁹ C = 3.2 × 10⁻¹⁹ C
Charge of the gold nucleus q₂= 79 × 1.6 × 10⁻¹⁹ = 1.264 × 10⁻¹⁷C
Kinetic energy of the alpha particle = 5.97 × 10⁶ × 1.602 × 10⁻¹⁹ J ( 1 eV) = 9.564 × 10⁻¹³
k electrostatic force constant = 9 × 10⁹ N.m²/c²
Kinetic energy = potential energy = k q₁q₂ / r where r is the closest distance the alpha particle got to the gold nucleus
r = ( 9 × 10⁹ N.m²/c² × 3.2 × 10⁻¹⁹ C × 1.264 × 10⁻¹⁷C) / 9.564 × 10⁻¹³ = 3.8 × 10 ⁻¹⁴ m
