Answer:
0.16Hz
Explanation:
wavelength (λ) = 125 meters
speed (V) = 20 m/s
frequency (F) = ?
Recall that frequency is the number of cycles the wave complete in one
second. And its value depends on the wavelength and speed of the wave.
So, apply the formula V = F λ
Make F the subject formula
F = V / λ
F = 20 m/s / 125 meters
F = 0.16 Hz
 
        
             
        
        
        
maximum allowed value of the speed in roller coaster is given as

now from kinematics we can say

here initial speed will be

acceleration is due to gravity

now we can use this to find the height



so maximum allowed height will be 20.4 m
 
        
             
        
        
        
Answer:
 a = 17.68 m/s²
Explanation:
given,
length of the string, L = 0.8 m
angle made with vertical, θ = 61°
time to complete 1 rev, t = 1.25 s
radial acceleration = ?
first we have to calculate the radius of the circle
  R = L sin θ
  R = 0.8 x sin 61°
  R = 0.7 m
now, calculating at the angular velocity 
 
 
   ω = 5.026 rad/s
now, radial acceleration
  a = r ω²
  a = 0.7 x 5.026²
  a = 17.68 m/s²
hence, the radial acceleration of the ball is equal to 17.68 rad/s²
 
        
             
        
        
        
Answer:
mu = 0.56
Explanation:
The friction force is calculated by taking into account the deceleration of the car in 25m. This can be calculated by using the following formula:

v: final speed = 0m/s (the car stops)
v_o: initial speed in the interval of interest = 60km/h 
     = 60(1000m)/(3600s) = 16.66m/s
x: distance = 25m
BY doing a the subject of the formula and replace the values of v, v_o and x you obtain:

with this value of a you calculate the friction force that makes this deceleration over the car. By using the Newton second's Law you obtain:

Furthermore, you use the relation between the friction force and the friction coefficient:

hence, the friction coefficient is 0.56
 
        
             
        
        
        
Wave D has the same wavelength as wave A, but the amplitude is lower. The answer is Wave D.