Electromagnets have certain advantages over permanent magnets. One of the major advantage is, the amount of electric current can easily be controlled, in turn, magnetic field can be controlled. Out of all the options, option D would be the best answer.
In short, Your Answer would be option D) Electromagnets can easily be turned on and off.
Hope this helps!
Answer:
D. The net electrical charge of the Earth.
Explanation:
All the other three choices affect the gravitational force. I remember from middle school.
Answer:
The position of the particle is 6m
The velocity of the particle is 16 m/s in negative direction
The acceleration of the object is -40 m/s²
Explanation:
Given;
motion of the particle along a straight line as x = 6 + 4t² - t⁴
The position of the object when t = 2s
x = 6 + 4(2)² - (2)⁴
x = 6 + 16 - 16
x = 6m
The velocity of the object when t = 2s
Velocity = dx/dt
dx/dt = 8t - 4t³
when t = 2s
Velocity = 8(2) - 4(2)³
Velocity = 16 - 32
Velocity = -16m/s
Velocity = 16 m/s (in negative direction)
The acceleration of the object when t = 2s
Acceleration = d²x/dt² = 8 - 12t²
Acceleration = 8 - 12 (2)²
Acceleration = -40 m/s²
Answer:
2d
Explanation:
For any instance equivalent force acting on the body is

Where
m is the mass of the object
k is the force constant of the spring
d is the extension in the spring
and
d/dt(dx/dt)= is the acceleration of the object
solving the above equation we get

where

A is the amplitude of oscillation from the mean position.
k= spring constant , T= time period
Here we are assuming that at t=T/4
x= 0 since, no extension in the spring
then
A=- d
Hence
x=- d sin wt + d
now, x is maximum when sin wt=- 1
Therefore,
x(maximum)=2d
Answer:
an example for applied force is
Explanation:
The applied force is the force applied to the object to either displace it or change its shape.