Words less true are seldom if ever spoken.
Answer:9.75 m/s
Explanation:
Given
Length of ladder 
Foot the ladder is moving away with speed of 
From diagram
------1
at 


Now differentiating equation 1 w.r.t time




negative indicates distance is decreasing with time
Answer:
Centripetal acceleration.
Explanation:
Centripetal acceleration is a property of a body moving in a uniform circular path and it is directed radially towards the center of the circle in which body is rotating.
The force which causes this acceleration is centripetal force which is also directed towards the center of the circle and pulls the body towards its center.
It is calculated through following formula

where v is velocity and r is the radius of the circle.
Answer: A and B
Explanation:
A
The wavelength of both transverse and longitudinal waves is measured parallel to the direction of the travel of the wave.
Because wavelength is the distance between the two successful crest or trough.
B)
Amplitude of longitudinal waves is measured at right angles to the direction of the travel of the wave and represents the maximum distance the molecule has moved from its normal position.
Because amplitude is the measure of maximum displacement from the original position