Sound waves travel at the rate of 343 m/s at 20°C. If a man standing 450 meters away from the wall of a canyon yells, “Hello,” h
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Answer:
D) 11 m/s
Explanation:
The problem asks us to calculate the velocity of the hot dog with respect to the observer stationary outside the train. This velocity is given by:
where
is the velocity of the train (towards right)
is the velocity of the man (towards right)
is the velocity of the hot-dog (towards left, so we put a negative sign)
Substituting the numbers into the equation, we find
and the positive sign means the velocity is toward right.
Answer:
(a) Total time will be 8.05 hour
(B) Total cost will be $417.6
Explanation:
We have given dryer uses 16 A of current so current i = 16 A
Voltage V = 240 volt
Time t = 45 minutes =45×60 = 2700 sec
So power P = VI = 240×16 = 3840 W
So energy E = power×time = 3840×45×60 = 9396 KJ
(A) Now current in the computer i = 2.7 A
Voltage V = 120 V
So power P = 120×2.7 = 324 W
Now computer is using energy of dryer
So time by which it will use energy is
So time will be 8.05 hour
(b) Cost per kilowatt is $0.12
So total cost =3480×0.12 = $417.6