Answer:
Since then only three elements on the periodic table have been found to be ferromagnetic at room temperature - iron (Fe), cobalt (Co), and nickel (Ni). The rare earth element gadolinium (Gd) nearly misses by only 8 degrees Celsius.
Explanation:
Answer:

Explanation:
Consider the motion of the ball attached to string.
In triangle ABD

height gained by the ball is given as

= mass of the ball attached to string = 110 g
= speed of the ball attached to string just after collision
Using conservation of energy
Potential energy gained = Kinetic energy lost

Consider the collision between the two balls
= mass of the ball fired = 26 g
= initial velocity of ball fired before collision = ?
= final velocity of ball fired after collision = ?
using conservation of momentum

Using conservation of kinetic energy

Answer:
6.2 ohm
Explanation:
Let R1 = 5 ohm
R2= 3 ohm
R3= 2 ohm
Since R3 and R2 are parallel then net resistance R' is given by
1/R' = 1/R2 + 1/R3
1/R' = 1/3 + 1/2
1/R' = 5/6
then
R' = 6/5 = 1.2 ohm
Now R1 and R' are in series, so
R = R1 + R'
R = 5 + 1.2
R = 6.2 ohm
Answer:
The constant force is 263.55 newtons
Explanation:
There's a rotational version of the Newton's second law that relates the net torque on an object with its angular acceleration by the equation:
(1)
with τ the net torque and α the angular acceleration. It’s interesting to note the similarity of that equation with the well-known equation F=ma. I that is the moment of inertia is like m in the linear case. The magnitude of a torque is defined as

with F the force applied in some point, r the distance of the point respect the axis rotation and θ the angle between the force and the radial vector that points toward the point the force is applied, in our case θ=90 and sinθ=1, then (1):
(2)
Because the applied force is constant the angular acceleration is constant too, and for constant angular acceleration we have that it's equal to the change of angular velocity over a period of time:

It's important to work in radian units so knowing that 
(3)
The moment of inertia of a disk is:
(4)
with M the mass of the disk and R its radius, then

using the values (3) and (4) on (2)
(2)
Because the force is applied about the rim of the disk r=R=1.50:
