Answer = A) fossil fuels
B and C are renewable types of energy
D is a type of fossil fuel, just like oil
Answer
given,
wavelength of the red light,λ = 687 nm
wavelength of the yellow light = 582 nm
Frequency of red light
=
=
= 4.36 x 10¹⁴ Hz
frequency of the yellow light
=
= 5.15 x 10¹⁴ Hz
speed of the car

v_r is the required speed.
v_r = 0.19 c
v_r = 0.19 x 3 x 10⁸ =5.7 x 10⁷ m/s
1 m/s = 2.23694 mile/hr
v_r = 1.27 x 10⁸ mile/hr
if the light is actually yellow
f₀ = 5.15 x 10¹⁴ Hz

f = 6.13 x 10¹⁴ Hz
wavelength corresponding to this frequency is wavelength = 493.2 nm
hence, the color corresponding to this wavelength is Green.
Answer:
Workdone =0
Explanation:
The body is inclined at θ=30°, s=10m, m=5kg
Workdone by the object = FsCosθ
but the surface is a friction-less surface, this means coefficient of friction =0
F=μR
F=0*R
F=0
W=FScosθ
W=0*SCosθ
W=0
Answer: B is right
Explanation: Heat Q = m Cv ΔT = 3.0 kg · 4186 J / (kg·K) · 30 K≈ 376 740 J
"Constant change of direction" simply means on a curve.
The examples provided don't show a durn thing.