Complete Question
The complete question is shown on the first uploaded image
Answer:
The time taken is 
Explanation:
From the question we are told that
The value of 
The the interior temperature is 
The external temperature is 
The required interior temperature is 
The newton cooling law is
=> 
Now integrate both sides we have
Since c is a constant lnC = c will also give a constant so
=> 
=> 
substituting value
Hence
=> 
240 = 0+1/2 (-9.8t
240 = -4.9t
<span>240/-4.9 = t</span><span>
</span>49.0 = t
t= 7.0s
Speed = distance/time
= 400/72
=5.55 m/s
The answer is <span>temperature, salinity
Hope this helps. :)</span>
Answer: V = 15 m/s
Explanation:
As stationary speed gun emits a microwave beam at 2.10*10^10Hz. It reflects off a car and returns 1030 Hz higher. The observed frequency the car will be experiencing will be addition of the two frequency. That is,
F = 2.1 × 10^10 + 1030 = 2.100000103×10^10Hz
Using doppler effect formula
F = C/ ( C - V) × f
Where
F = observed frequency
f = source frequency
C = speed of light = 3×10^8
V = speed of the car
Substitute all the parameters into the formula
2.100000103×10^10 = 3×10^8/(3×10^8 -V) × 2.1×10^10
2.100000103×10^10/2.1×10^10 = 3×108/(3×10^8 - V)
1.000000049 = 3×10^8/(3×10^8 - V)
Cross multiply
300000014.7 - 1.000000049V = 3×10^8
Collect the like terms
1.000000049V = 14.71429
Make V the subject of formula
V = 14.71429/1.000000049
V = 14.7 m/s
The speed of the car is 15 m/s approximately.
