Answer:
The correct option is that (She decreases her moment of inertia, thereby increasing her angular speed.)
Explanation:
When an object is in circular motion, the vector that describes it is known as angular momentum. Angular momentum is conserved or constant when an object is spinning in a closed system and no external torques are applied to it. An example of conservation of angular momentum is seen when a woman is sitting on a spinning piano stool with her arms extended. Her angular momentum is conserved because the net torque on her is negligibly small as the friction is exerted very close to the pivot point.
When she folds her arms,her rate of spin increases greatly decreasing her moment of inertia. The work she does to pull in her arms results in an increase in rotational kinetic energy( that is, increase in her angular speed). I hope this helps, thanks!
K.E = 1/2 mv²
100 = 1/2 (2 )(v)²
100 = both 2 cancel (v)²
Taking Square root on b/s
√100 = √v²
10 = v
Answer:
52.5 J
Explanation:
Work done (W) is the product of the force (F) applied on a body and the distance (s) moved in the direction of the force.
i.e W = F × s
It is a scalar quantity and measured in Joules (J).
Given that: F = 35.0 N and s = 1.50 m, then;
W = F × s
W = 35.0 × 1.5
= 52.5 J
Therefore, the work done on the sleigh by Samuel is 52.5 J.
physics
:p
Mechanical energy is commonly referred to as "the ability to do work." This is a somewhat inaccurate (though still useful) idea of it, as I'll describe.
Mechanical energy is the sum of kinetic energy (energy associated with motion) and potential energy (energy associated with position). Technically speaking, heat energy (the most common example of non-mechanical energy) is small-scale kinetic energy, but for macroscopic systems, this energy is not mechanical. Although it has the ability to do work, it is small-scale and thus not considered "mechanical."
As far as how mechanical energy is transformed into nonmechanical energy, let me provide a couple of examples:
One is the classic example of friction. When two surfaces rub together, they generate thermal energy, or heat. This is a transformation of the mechanical kinetic energy of the objects into the thermal non-mechanical energy (which is small-scale kinetic energy). This is the primary reason why there are no perfect machines--some energy is always lost as heat due to friction.
Another example is a small electric generator. Rotating a small circuit in a magnetic field will induce a voltage and generate electrical non-mechanical energy. This is a transformation of the kinetic energy associated with the rotation into electrical energy.
The primary difference between mechanical energy and non-mechanical energy is the scope. Mechanical energy is generally associated with macroscopic objects (like water wheels), while non-mechanical energy is generally on the sub-microscopic scale (the kinetic energy of individual atoms). Both can do work, though working with mechanical energy is generally more helpful than trying to work with non-mechanical energy.
Explanation:
Given that,
Mass of the block, m = 12.2 kg
Initial velocity of the block, u = 6.65 m/s
The coefficient of kinetic friction, 
(a)The force of kinetic friction is given by :
mg is the normal force
So,
(b) Net force acting on the block in the horizontal direction,
f = ma
a is the acceleration of the block
(c) Let d is the distance covered by the block before coming to the rest. Using third equation of motion as follows :
Hence, this is the required solution.
