While pulling a bicycle out of the garage, you must pull it a total of 1.7 m with a force of 27 n. how much work are you doing o
2 answers:
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(a) The electrons move horizontally from west to east, while the magnetic field is directed downward, toward the surface. We can determine the direction of the force on the electron by using the right-hand rule:
- index finger: velocity --> due east
- middle finger: magnetic field --> downward
- thumb: force --> due north
However, we have to take into account that the electron has negative charge, therefore we have to take the opposite direction: so, the magnetic force is directed southwards, and the electrons are deflected due south.
b) From the kinetic energy of the electrons, we can find their velocity by using
where K is the kinetic energy, m the electron mass and v their velocity. Re-arranging the formula, we find
The Lorentz force due to the magnetic field provides the centripetal force that deflects the electrons:
where
q is the electron charge
v is the speed
B is the magnetic field strength
m is the electron mass
r is the radius of the trajectory
By re-arranging the equation, we find the radius r:
And finally we can calculate the centripetal acceleration, given by:
- index finger: velocity --> due east
- middle finger: magnetic field --> downward
- thumb: force --> due north
However, we have to take into account that the electron has negative charge, therefore we have to take the opposite direction: so, the magnetic force is directed southwards, and the electrons are deflected due south.
b) From the kinetic energy of the electrons, we can find their velocity by using
where K is the kinetic energy, m the electron mass and v their velocity. Re-arranging the formula, we find
The Lorentz force due to the magnetic field provides the centripetal force that deflects the electrons:
where
q is the electron charge
v is the speed
B is the magnetic field strength
m is the electron mass
r is the radius of the trajectory
By re-arranging the equation, we find the radius r:
And finally we can calculate the centripetal acceleration, given by:
Answer:
A. potential energy is 258720 Joule
Explanation:
A.Gravitational potential energy is: PE = m × g × h
velocity = 15.33 m/s when the car reaches the bottom of the hill.
where, m = mass
g = acceleration due to gravity
h = height from the bottom of hill.
The potential energy is : m×g×h
=(2200×9.8×12)
=258720 Joule
B. at the bottom of the hill, the potential energy is converted into kinetic energy so PE at top = KE at bottom
kinetic energy= (
)
where v = velocity
m= mass
therefore, v=
or, v=
or, v=15.33 m/s