Answer:
3. Her angular speed increases because her angular momentum is the same but her moment of inertia decreases
Explanation:
II ωi the intial angular momentum of the skater. Her angular momentum changes to If ωf after pulling her arms in.
It must be noted that If is less than II, then it is because her arms now go round not far from the rotation axis which brings down the mementos of inertia.
Angular momentum does not change since torque is O.
Note: the mathematical representations are better written on the attached diagram.
Answer:
The velocity with which the mass will hit the floor is 
Explanation:
If the tension in the string is
, for
we have
,
and for the mass

From these equations we solve for
and get:

The kinematic equation

gives the final velocity
of a particle, when its initial velocity was
, and has traveled a distance
while undergoing acceleration
.
In our case
(the initial velocity of the particles is zero)

which gives us



which is the velocity with which the mass
will hit the floor.
Answer:
a = 6.53 m/s^2
v = 11.5689 m/s
Explanation:
Given data:
engine power is 217 hp
70 % power reached to wheel
total mass ( car + driver) is 1530 kg
from the data given
2/3 rd of weight is over the wheel
w = 2/3rd mg
maximum force

we know that F = ma


the new power is 


solving for speed v

![v = 0.7 \frac{217 [\frac{746 w}{1 hp}]}{1500 \times 6.53}](https://tex.z-dn.net/?f=v%20%3D%200.7%20%5Cfrac%7B217%20%5B%5Cfrac%7B746%20w%7D%7B1%20hp%7D%5D%7D%7B1500%20%5Ctimes%206.53%7D)
v = 11.5689 m/s
The answer is B. 1,4, and 6
Answer:
Oscillation whose amplitude reduce with time are called damped oscillation. This happen because of the friction. In oscillation if its amplitude doesn't change with time then they are called Undamped oscillation