Answer:
(1) 1×10⁻⁴
Explanation:
From the question,
α = (ΔL/L)/(ΔT)............. Equation 1
Where α = linear expansivity of the metal plate, ΔL/L = Fractional change in Length, ΔT = Rise in temperature.
Given: ΔL/L = 1×10⁻⁴, ΔT = 10°C
Substitute these values into equation 1
α = 1×10⁻⁴/10
α = 1×10⁻⁵ °C⁻¹ .
β = (ΔA/A)/ΔT................... Equation 2
Where β = Coefficient of Area expansivity, ΔA/A = Fractional change in area.
make ΔA/A the subject of the equation
ΔA/A = β×ΔT.......................... Equation 3
But,
β = 2α.......................... Equation 4
Substitute equation 4 into equation 3
ΔA/A = 2α×ΔT................ Equation 5
Given: ΔT = 5°C, α = 1×10⁻⁵ °C⁻¹
Substitute into equation 5
ΔA/A = ( 2)×(1×10⁻⁵)×(5)
ΔA/A = 10×10⁻⁵
ΔA/A = 1×10⁻⁴
Hence the right option is (1) 1×10⁻⁴
Answer: 0.4 km/h
100 m = 0.1 km
15min./60min. = 0.25 hr
so, divide the total distance (100 m) by the total time (15 min)
0.1 km/0.25 hr = 0.4
(power)
kinetic energy
law of Conservation of Energy
energy
(mechanical)
(potential energy)
gravitation or gravity
work
(I don't know the last one; it's somebody's law)
0.0035% of it is actually visible to us
your answer should be weakest and attractive
