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:
It's either B or D, I'm not positive which it is
Explanation:
Answer: He would reach 7m/s at the distance of 17,5m.
Explanation: In order for us to know how long it takes for the speed to be reached, we use the equation V= Vo + at, with V=7m/s, Vo= 0m/s since you start from rest and a=1.4m/s². T is the time in seconds that we want to find out.
7 = 0 + 1.4t
7 = 1.4t
t= 5s
Now, we want to know the distance this boy reaches in 5 seconds, in a 7m/s speed and accelarating in 1.4m/s². For finding this out, we use another equation, S = So + Vot + (at²)/2, S being the final distance, So = 0m because he started from rest, and the other variables used before.
S = 0 + 0*5 + [1.4*(5²)]/2
S = 0 + 0 + (1.4*25)/2
S = 35/2
S = 17,5m
HUHHHHHHHHHHHHHHHHHHHHH????????
Answer:
Explanation:
This question pertains to resonance in air column. It is the case of closed air column in which fundamental note is formed at a length which is as follows
l = λ / 4 where l is length of tube and λ is wave length.
here l = .26 m
λ = .26 x 4 = 1.04 m
frequency of sound = 330 Hz
velocity of sound = frequency x wave length
= 330 x 1.04
= 343.2 m /s
b )
Next overtone will be produced at 3 times the length
so next length of air column = 3 x 26
= 78 cm
c )
If frequency of sound = 256 Hz
wavelength = velocity / frequency
= 343.2 / 256
= 1.34 m
= 134 cm
length of air column for resonance
= wavelength / 4
134/4
= 33.5 cm
