the radiogenic heat produced by the radioactive decay of isotopes in the mantle and crust, and the primordial heat left over from the formation of the Earth.
Your position in meters will, measured relative to the starting point of the car behind you, be
x1(t) = 10 + 23.61 t - 1/2 4.2 t^2
his position will be
x2(t) = 16.67 t
Hence at any time the separation s(t) will be
s(t) = x1(t) - x2(t) = 10 + 6.94 t -2.1 t^2
Now I assume you mean that you will decelerate UNTIl you are driving at the legal speed limit (60 km/h). That will take you:
16.67 m/s = 23.61m/s - 4.2 m/s^2 * t
t = 1.65 seconds
What is the separation at that time? If it is still greater than zero, there will be no collision:
s(1.65) = 10 + 6.94 *1.65 -2.1 (1.65)^2 = 15.73 meters.
Hence you will NOT collide. The 1.65 s you calculated was the time needed to brake to the speed of 60 km/h.
The best and most correct answer among the choices provided by your question is the first choice or letter A.
<span>The best method to estimate the speed at which a star is moving away from Earth is to measure the star's red shift.</span>
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Answer:
S = 2266.67 m/s
Explanation:
Given,
length of the metal = 3.4 m
pulses are separated in time = 8.4 ms
speed of sound in air= 343 m/s
speed of sound in this metal = ?
time taken
t = 9.9 ms
speed of sound in the metal is fast
t = 9.9 - 8.4 = 1.5 ms
time for which sound is in metal is equal to 1.5 ms
speed of sound in metal
S = 2266.67 m/s
Speed of sound in metal is equal to S = 2266.67 m/s
