Answer:
Explanation:
We are given that
Initial velocity=u=18ft/s
Final velocity,v=38ft/s
Time=t=3 s
We have to find the average acceleration over that 3 s period.
We know that
Average acceleration,a=
Using the formula
Average acceleration,a=
Average acceleration,a=
Average acceleration,a=
Hence, the average acceleration=
Answer:
630cm/s
Explanation:
In simple harmonic motion, the tangential velocity is expressed mathematically as v = ὦr
ὦ is the angular velocity = 2πf
r is the radius of the disk
f is the frequency
Given the radius of disk = 10cm
frequency = 10Hz
v = 2πfr
v = 2π×10×10
v = 200π
v = 628.32 cm/s
The tangential velocity = 630cm/s ( to 2 significant figures)
Answer:
The hairs would have acquired charge by the passing of dry winds resulting in the loss of electron.
Explanation:
While standing on the top of a mountain if a person gets its hairs stand up after a cloud passes over, this might happen due to the static electric charges on the lower surface of the cloud are opposite in nature to that of hairs which the hairs would have acquired by the passing of dry winds which would have resulted in the loss of electron from the hair tip.
Similar case happens when we rub a dry plastic ruler or a dry plastic comb on our hairs.
The answer is:
B)They are in the same group because they have similar chemical properties, but they are in different periods because they have very different atomic numbers.
The explanation:
The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties.
A period is a horizontal row of elements on the periodic table. For example, the elements sodium ( Na ) and magnesium ( Mg ) are both in period 3. The elements astatine ( At ) and radon ( Rn ) are both in period 6.
