Answer:
t = 2.5 hours
Explanation:
given,
speed of the bike for t time= 18 mi/h
final speed of the bike after t time = 12 mi/h
total distance, D = 69 miles
total time, T= 4.5 hour
time for which speed of the bike is 18 mi/h = ?
we know distance = speed x time
now,
18 x t + 12 (4.5 - t) = 69
6 t + 54 = 69
6 t = 15
t = 2.5 hours
The bike was at the speed of 18 mi/h for 2.5 hours.
Answer:
a) B=0.008 T
b) +z direction
Explanation:
<u>solution:</u>
a) The magnetic force:
F=i*l*B
Solve for B:
B=0.008 T
b) According to the left hand rule, the magnetic field is in the +z direction
Answer:
<h2>the ans...is dc circuit...</h2>
Answer:
the high temperature needed to operate this refrigerator is C) 137.4° C
Explanation:
Hello!
The carnot refrigeration cycle is one in which a machine absorbs heat from an enclosure and expels it to the surroundings, the equation that defines the COP performance coefficient for this cycle is:

COP=performance coefficient =2.1
T1= Low temperature
T2=high temperature
Now use algebra to find the high temperature

If we replace the values:
note = remember that the temperature must be in absolute units, for which we must add 273.15 to the low temperature to find the temperature in Kelvin
T1 = 5 + 273.15 = 278.15K

In celsius
T2=410.60-273.15=137.4° C
the high temperature needed to operate this refrigerator is C) 137.4° C
Answer:
i) 2
ii) No
Explanation:
i) The man will hear two sounds: one through the rail, and one in the air.
ii) The sounds will not reach the man at the same time. Sound travels faster through solids than through gases, so he will hear the sound through the rail before he hears the sound in the air.