Answer:
12 miles per hour 
Explanation:
time is equal to speed times distance 
 
        
                    
             
        
        
        
Fk = μK N
N = m a
N = 4 × a 
N = 4a
Fk = μK N
17 = 5 × 4a
17 = 20 a
a = ¹⁷/₂₀ = 0.85 m/s²
        
             
        
        
        

➡ 150hrs.

➡ Time = distance × speed 
➡ Time = 15*10
➡ Time = 150hrs ans. 
 
        
             
        
        
        
Answer:
λ = 596 nm.
Explanation:
Fringe width = λ D / d
λ is wave length , D is screen distance and d is slit separation. 
Putting the values 
1.62 x 10⁻² =(  λ x 5.3 ) / .195 x 10⁻³

λ = 596 nm.
 
        
             
        
        
        
The distance travel is 69.5 meters.
<u>Explanation:</u>
Given datas are as follows
Speed = 27.8 meters / second
Time = 2.5 seconds
The formula to calculate the speed using distance and time is
Speed = Distance ÷ Time (units)
Then Distance = Speed × Time (units)
Distance = (27.8 × 2.5) meters          
Distance = 69.50 meters
Therefore the distance travelled is 69.50 meters.