Distance = speed / time
speed = 95 m/s
time = 3 s
distance = 95 / 3 m
displacement = 95/3 m or 32 m (2 s.f.)
This question is incomplete, the complete question is;
The wings of some beetles have closely spaced parallel lines of melanin, causing the wing to act as a reflection grating. Suppose sunlight shines straight onto a beetle wing.
If the melanin lines on the wing are spaced 2.0 μm apart, what is the first-order diffraction angle for green light (λ = 550 nm)?
Answer:
the first-order diffraction angle for green light is 15.96°
Explanation:
Given the data in the question;
from diffraction theory;
nλ = dsin∅
where n is the diffraction order ( 1st order = 1 )
λ is the wavelength ( 550 nm = 550 × 10⁻⁹ m)
d is the grating spacing ( 2.0 μm = 2.0 × 10⁻⁶ m )
∅ is the diffraction angle ( ? )
so we substitute
nλ = dsin∅
sin∅ = nλ / d
sin∅ = (1 × 550 × 10⁻⁹ m) / 2.0 × 10⁻⁶ m
sin∅ = 0.275
∅ = sin⁻¹(0.275)
∅ = 15.96°
Therefore, the first-order diffraction angle for green light is 15.96°
Answer:
The buoyant force on the wood = 7.652 N
Explanation:
According to the principle of flotation, a body floats when the upthrust exerted upon it by the fluid n which it floats equals the weight of the body.
W = U ............... Equation.
Where W = weight of the wood, U = Upthrust or buoyant force.
Recall That,
Density = mass/volume
Mass = Density×volume
m = D×V........................ Equation 2
Where m = mass of the wood, V = Volume of the wood, D = Density of the wood.
But
Volume of a cube = a³
V = a³ where a = length of the cube.
V = 10³ = 1000 cm³.
Given: V = 1000 cm³ D = 0.780 g/cm³
Substituting these values into equation 2,
m = 1000(0.780)
m = 780 g
m = 0.78 kg.
But W = mg
Where m = 0.78 kg, g = 9.81 m/s²
W = 0.78(9.81)
W = 7.652 N.
Since W = U = 7.652 N.
U = 7.652 N
Therefore the buoyant force on the wood =7.652 N
