Answer:
Pi(3.14) radians or 180º degrees
Explanation:
First of all, we need to obtain the wavelength of a wave traveling to the speed of sound and 420 Hz of frequency.
The formula is:

where l = wavelength in meters
With current values:
l = 336 [m/s]/420[1/s] = 0.8 meters
Since a complete cycle (360º or 2pi radians) needs 0.8 meters to complete, 0.4 meters or 40 cm is just half of it, making a 180º degree phase or 3.14 radians.
the less porous, the less permeable
One atom on nitrogen because there isn’t a number directly after it’s the 3 signifies that there is three groups of those atoms as a total
Answer:
Option A
Explanation:
Velocity is expressed as distance covered per unit time, with respect to direction. Therefore, v=d/t
Given distance west as 60 km and time as 1.33 then velocity will be
V=60/1.33=45.112781954887 km/h
Rounded off as 45.11 km/h West
Velocity in East will also be given by substituting 40 km for d and 0.67 h for h hence
V=40/0.67=59.701492537313 km/h rounded off as 59.70 km/h East
Taking East as positive then West as negative, the sum of two velocities will be (59.70+-45.11)/2=7.295 km/h East
Approximately 10 km/h East since it is positive
Answer:
F= 4788 N
Explanation:
Because the car moves with uniformly accelerated movement we apply the following formula:
vf²=v₀²+2*a*d Formula (1)
Where:
d:displacement in meters (m)
v₀: initial speed in m/s
vf: final speed in m/s
a: acceleration in m/s²
Data
d=36.9 m
v₀=14.0 m/s m/s
vf= 0
Calculating of the acceleration of the car
We replace dta in the formula (1)
vf²=v₀²+2*a*d
(0)²=(14)²+2*a*(36.9)
-(14)²= (73.8) *a
a= - (196) / (73.8)
a= - 2.66 m/s²
Newton's second law of the car in direction horizontal (x):
∑Fx = m*ax Formula (2)
∑F : algebraic sum of the forces in direction x-axis (N)
m : mass (kg)
a : acceleration (m/s²)
Data
m=1800 Fkg
a= - 2.66 m/s²
Magnitude of the horizontal net force (F) that is required to bring the car to a halt in a distance of 36.9 m :
We replace data in the formula (2)
-F= (1800 kg) * ( -2.66 m/s²
)
F= 4788 N