Answer:
The value is 
Explanation:
From the question we are told that
The speed of the marathon runner is 
The distance from the distance from the finish is 
The speed of the bird is 
Generally the time taken for the runner to reach the finish is mathematically represented as



So the distance covered by the bird is



Answer:
The size of the force developing inside the steel rod is 32039.28 N
Explanation:
Given;
length of the steel rod, L = 1.55 m
cross sectional area of the steel, A = 4.89 cm²
temperature change, ∆T = 28.0 K
coefficient of linear expansion for steel, α = 1.17 × 10⁻⁵ 1/K
Young modulus of steel, E = 200.0 GPa.
Extension of the steel is given as;
α ∆T L = FL / AE
α ∆T = F/AE
F = AEα ∆T
F = ( 4.89 x 10⁻⁴)(200 x 10⁹)(1.17 × 10⁻⁵)(28.0 K)
F = 32039.28 N
Therefore, the size of the force developing inside the steel rod when its temperature is raised, is 32039.28 N
The answer 1 is
The best-known use of radio waves is for communication; television, cellphones and radios all receive radio waves and convert them to mechanical vibrations in the speaker to create sound waves that can be heard.Electromagnetic radiation is transmitted inwaves or particles at different wavelengths and frequencies.
the answer 2 is
Radio Waves: Instant Communication
Microwaves: Data and Heat
i think the answer number 3 is
It is all about wavelength versus tunnel diameter. The wavelength of GPS is about 20cm it would happily propagate in any normal tunnel if it could get in but the earth and other structures absorb it. AM radio (600kHz - 1500kHz) cannot propagate in any normal tunnel because the wavelength is too long (500m-200m) relative to the diameter, and thus gets reflected at the entrance. FM (100MHz ~ 3m) would propagate and it does for a while but then it suffers reflections