Answer question number 78

Physics

1 answer:

madreJ [45]3 years ago

4 0

The two ends (the ends of the north and south poles) are the most powerful parts of the magnet. They have the strongest magnetic force. As you go down the magnet (closer to the center) the magnet loses its magnetism strength.
(hope it helps ^_^)

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Forces and pres

Sliva [168]

Answer:

A. It is zero.

Explanation:

D Later in the day, more power is developed in lifting each box. 12 A manometer is used to indicate the pressure in a steel vessel, as shown in the diagram. What value does the liquid manometer give for the pressure in the vessel? It is zero

5 0

2 years ago

The electrons in the beam of a television tube have a kinetic energy of 2.20 10-15 j. initially, the electrons move horizontally

dalvyx [7]

(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
$K= \frac{1}{2}mv^2$
where K is the kinetic energy, m the electron mass and v their velocity. Re-arranging the formula, we find
$v= \sqrt{ \frac{2K}{m} }= \sqrt{ \frac{2 \cdot 2.20 \cdot 10^{-15} J}{9.1 \cdot 10^{-31} kg} }=6.95 \cdot 10^7 m/s$

The Lorentz force due to the magnetic field provides the centripetal force that deflects the electrons:
$qvB = m \frac{v^2}{r}$
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:
$r= \frac{mv}{qB}= \frac{(9.1 \cdot 10^{-31} kg)(6.95 \cdot 10^7 m/s)}{(1.6 \cdot 10^{-19} C)(3.00 \cdot 10^{-5} T)}=13.18 m$

And finally we can calculate the centripetal acceleration, given by:
$a_c = \frac{v^2}{r}= \frac{(6.95 \cdot 10^7 m/s)^2}{13.18 m}=3.66 \cdot 10^{14} m/s^2$

5 0

3 years ago

The ____ of a position-time graph represents an object’s velocity.

Marianna [84]

Answer:

The slope of a position-time graph represents an object’s velocity.

Explanation:

In a position-time graph, the values on the x-axis represent the time, while the values on the y-axis represent the position of the object.

Velocity is defined as the ratio between the displacement of an object and the time taken:

$v=\frac{\Delta s}{\Delta t}$

However, we can see that this definition corresponds to the slope of the curve in a position-time graph. In fact:

$\Delta s$ , the displacement, corresponds to the difference in position, so the difference between the values on the y-axis: $\Delta s=y_2 -y_1$

$\Delta t$ , the time interval, corresponds to the difference in times, so the difference between the values on the x-axis: $\Delta t= t_2 -t_1=x_2 -x_1$