Dinosaurs lived between 230 and 65 million years ago, in a time known as the Mesozoic Era<span>. This was many millions of years before the first modern humans, Homo sapiens, appeared. </span>
Answer: D. plant more trees where forests are cut down.
Explanation:
Deforestation has to do with the cutting down of trees. Cutting down the forest reduces the size of animal habitats, increases erosion, and results in an increase in the amount of carbon dioxide in the atmosphere.
Ok order to tackle the above, it is necessary that we should plant more trees where forests are cut down.
Answer:
Explanation:
Let us study the downward movement of cylinder which accelerates as well as rotates .
A)
If v be the linear downward velocity of cm of cylinder and ω be angular velocity of cylinder
v = ωr , when there is no slippage of string around cylinder.
B &C )
Total kinetic energy = Rotational + linear
= 1/2 Iω² + 1/2 m v²
1/2 x1/2 mr²ω² +1/2 m v²
= 1/4 mv² +1/2 m v²
= 3/4 m v²
For downward acceleration ,
mg - T = ma where T is tension in string.
Rotational movement
Torque = T x r
Tr = I α , I is moment of inertia and α is angular acceleration .
= I a/r
T = I a / r² , Putting this value of T in earlier equation
mg - I a / r² = ma
a (I / r² +m )= mg
a = mg / (I / r² +m )
For cylinders
I = .5 mr²
a = g / (.5 +1)
= g / 1.5
-1.5 m/s^2 x 1.2 seconds = -1.8 m/s
It is a negative value which means the object slowed down. The object would have originally been going that amount more.
5.0 + 1.8 = 6.8 m/s
answer: 6.8 m/s
