Answer:
The power required to move each bale is 30 lbf.ft/sec.
Explanation:
F= 40lbf * sin (30º)
F=20lbf
P= F*v
P=20 lbf * 1.5 ft/sec
P= 30 lbf.ft/sec
Answer:Point B
Explanation:When it is at the bottom of its swing (arm straight up and down). When it is at its lowest point, Gravity can not pull it down any further. This position also has the most kinetic energy because after it passes the bottom, it goes back up again and loses speed. so when the pendulum is at the bottom it is traveling the fastest it will go.
Work, Kinetic Energy and Potential Energy
6.1 The Important Stuff 6.1.1 Kinetic Energy
For an object with mass m and speed v, the kinetic energy is defined as K = 1mv2
2
(6.1)
Kinetic energy is a scalar (it has magnitude but no direction); it is always a positive number; and it has SI units of kg · m2/s2. This new combination of the basic SI units is
known as the joule:
As we will see, the joule is also the unit of work W and potential energy U. Other energy
1joule = 1J = 1 kg·m2 (6.2) s2
units often seen are:
6.1.2 Work
1erg=1g·cm2 =10−7J 1eV=1.60×10−19J s2
When an object moves while a force is being exerted on it, then work is being done on the object by the force.
If an object moves through a displacement d while a constant force F is acting on it, the force does an amount of work equal to
W =F·d=Fdcosφ (6.3)
where φ is the angle between d and F.
The plastic rod is made of insulator (plastic), so it does not allow charges moving from one sphere to another. This means that all the electrons given to sphere A will remain on sphere A.
The number of electrons initially given to sphere A is
, and since the charge of 1 electron is
, the net charge left on sphere A after the removal of the rod will be
