Starting from rest, how far will a brick fall if it is going 15 m/s and accelerates at a rate of 9.8 m/s2?
1 answer:
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Answer:
Speed = 0.00392 m/s
Explanation:
Solution:
Frequency of the radio = 85 MHz
If we have the frequency, we can calculate the wavelength of the radio wave.
As we know,
Frequency = speed of light/wavelength
wavelength = c/f
c = speed of light = 3 x m/s
So,
Wavelength = 3 x m/s / 85 x
Hz
Wavelength = 3.5294 m
Man gets disturbed reception at t = 15 min
t = 15 x 60 = 900 s
t = 900 s
Speed = distance/time
Here, distance is wavelength. So,
Speed = 3.5294 m / 900 s
Speed = 0.00392 m/s
Hence, the man's car is going with speed of 0.00392 m/s
Answer:
t ’= , v_r = 1 m/s t ’= 547.19 s
Explanation:
This is a relative velocity exercise in a dimesion, since the river and the boat are going in the same direction.
By the time the boat goes up the river
v_b - v_r = d / t
By the time the boat goes down the river
v_b + v_r = d '/ t'
let's subtract the equations
2 v_r = d ’/ t’ - d / t
d ’/ t’ = 2v_r + d / t
In the exercise they tell us
d = 1.22 +1.45 = 2.67 km= 2.67 10³ m
d ’= 1.45 km= 1.45 1.³ m
at time t = 69.1 min (60 s / 1min) = 4146 s
the speed of river is v_r
t ’=
t ’=
In order to complete the calculation, we must assume a river speed
v_r = 1 m / s
let's calculate
t ’=
t ’= 547.19 s