Magnetism is the product of a moving charged particle. We can have electricity without magnetism but we can not have magnetism without electricity.An electro magnet is made so that we have a soft metal core and electricity around it. A bar magnet is a normal magnet in bar shape with permanent magnetism.
Answer:
Frictional force, F = 45.9 N
Explanation:
It is given that,
Weight of the box, W = 150 N
Acceleration, 
The coefficient of static friction between the box and the wagon's surface is 0.6 and the coefficient of kinetic friction is 0.4.
It is mentioned that the box does not move relative to the wagon. The force of friction is equal to the applied force. Let a is the acceleration. So,



Frictional force is given by :


F = 45.9 N
So, the friction force on this box is closest to 45.9 N. Hence, this is the required solution.
I think one hour, sorry if i'm wrong
Answer:
option B
Explanation:
given,
Force exerted by the hydraulic jack piston = F₁ = 250 N
diameter of piston, d₁ = 0.02 m
r₁ = 0.01 m
diameter of second piston, d₂ = 0.15 m
r₂ = 0.075 m
mass of the jack to lift = ?
now,




F₂ = 14062.5 N
F = m g


m = 1435 Kg
hence, the correct answer is option B
Wavelength = (speed) / (frequency)
Wavelength = (340 m/s) / (600 /s)
Wavelength = 0.567 meter