Answer:1200 kg
Explanation:
Given
Electromagnet can lift a mass of 
Magnetic force necessary to hold mass is proportional to Magnetic field
and magnetic field (B) is proportional to NIA
where N=no of turns
I=current in the magnet
A=area of cross-section
When we double the no of turns and triple the current then
N becomes 2 N
I becomes 3 I
therefore magnetic field becomes 6 times
Thus magnetic force becomes 6 times and we can say that electromagnet can hold the 6 times of given weight
i.e. 
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
Answer:
v = 2 v₀
Explanation:
For this exercise we will use the relationship between work and the change in kinetic energy
W = ΔK
Where the work is of the friction force, which is always opposed to the movement whereby the angle is 180º
W = - fr x
The distance for the first case is
x = 1/4 L
We substitute
-fr ¼ L = ½ m v₀²
fr L = 2 m v₀²
In the second case, the new speed takes the ball the entire distance
x = d
-fr L = ½ m v²
We equal the two equations
2 m v₀² = ½ m v²
v² = 4 v₀²
v = 2 v₀
The air particle inside the balloon will collide more with each other and the temperature inside the balloon will increase.
As a person squeezed and applies the pressure to the outside of a balloon, the air particle inside the balloon gains energy and collide with each other, the particle of the air also try leave the balloon surface will implies equal pressure on the wall of the balloon, as the pressure outside the balloon increase, the inside pressure will also increase.
