We use the equation of motion,
Here, S is the height, u is initial velocity and a is acceleration.
Given, 
As acorn falls from tree, therefore we take the value of 
and initial velocity 
.
Substituting these values in equation of motion,
Thus, the time taken by the acorn to fall 20 feet ( 6.096 m ) is 1.12 s.
Answer:
A wavelength is a measure of distance between two consecutive crests or trough. So , the unit of wavelength is same as unit of distance. I.e metre
Answer:1.63 m
Explanation:
Given
mass of block 
inclination 
Amount of work done 
block slides a distance s along the Plane
Work done =change in Potential Energy
Increase in height of block is 
Change in Potential Energy 
Answer: TheTroposphere contains 80% of the total gas in the atmosphere
We know that speed equals distance between time. Therefore to find the distance we have that d = V * t. Substituting the values d = (72 Km / h) * (1h / 3600s) * (4.0 s) = 0.08Km.Therefore during this inattentive period traveled a distance of 0.08Km
