Answer:
In terms of distance, average speed is 20 km/h
In terms of displacement, average speed is 0 km/h.
Explanation:
Total distance:

Total time is 3.0 hours
but:

In terms of distance.
substitute:


In terms of displacement:

 
        
             
        
        
        
Answer:
ramp b requires less force than ramp a
Explanation:
 
        
             
        
        
        
Answer:
A. False, frequency can increase or decrease wavelength. 
For example: a high frequency would mean there are shorter wavelengths that occur in a period. Meanwhile, a low frequency would indicate that the wavelengths are longer and in longer periods.
 
        
             
        
        
        
The colour we see is a measure of the wavelengths of light nor absorbed by the cloth. We would call the colour of the cloth blue if it absorbed longer wavelengths of yellow/orange/red. Sunlight contains all the visible wavelengths. Whatever is not absorbed is reflected.