answer;
The hole in the center of the washer will expand
explanation;
<em>A flat metal washer is heated. As the washer's temperature increases, what happens to the hole in the center? A flat metal washer is heated. As the washer's temperature increases, what happens to the hole in the center? The hole in the center will remain the same size. Changes in the hole cannot be determined without know the composition of the metal. The hole in the center of the washer will expand. The hole in the center of the washer will contract.</em>
this is an example of area expansivity.
coefficient of area expansivity is change in area per area per degree rise in temperature
a=dA/(A*dt)
as the temperature rises , there will be volumetric and area expansivity on the body. volume also increases because of the intermolecular forces of attraction between the molecule is now getting apart.
Explanation:
It is given that,
Mass of Madeleine, 
Initial speed of Madeleine, 
(due east)
Final speed of Madeleine, 
(due west)
Mass of Buffy, 
Final speed of Buffy, 
(due east)
Let 
is the Buffy's velocity just before the collision. Using the conservation of linear momentum as :
So, the initial speed of the Buffy just before the collision is 7.13 m/s and it is moving due west. Hence, this is the required solution.
This question deals with the law of conservation of momentum, which basically says that the total momentum in a system must stay the same, provided there are no outside forces. Since you were given the mass and velocity of the two objects you can find the momentum (p=mv) of each and then add them together to find the total momentum of the system before they collide. This total momentum must be the same after they collide. Since you have the mass and velocity of one of the objects after the collision you can find the its momentum after. Subtract this from the the system total and you will have the momentum of the other object after the collision. Now that you know the momentum of the other object you can find its velocity using p=mv and its mass from before.
Be careful with the velocities. They are vectors, so direction matters. Typically moving to the right is positive (+) and moving to the left is negative (-). It is not clear from your question which direction the objects are moving before and after the collision.
Explanation:
It is given that,
Area of square coil, 
Side of the square, L = 0.02 m
Number of turns, N = 10000
Uniform magnetic field, B = 1.5 T
Speed, v = 100 m/s
An emf is induced in the coil which is given by :
E = 30000 V
Breakdown voltage of air, 
Let d is the gap between the two wires connected to the ends of the coil and still get a spark. So,
Electric field, 
d = 0.075 m
Hence, this is the required solution.
