I think this must be if i remember The huge amounts of smoke and ash often seen billowing from active volcanoes generally travel vertically, carried upward by the powerful thermal updrafts volcanoes generate. There are two major types of pyroclastic flows. The first actually comes from the collapse of one of the typical columns of smoke and ash from a volcano. This is the fastest and most energetic type, caused when the weight of the material in the column is too much for the air pressure to support.
The other type of pyroclastic flow is caused by the collapse of a lava dome, the swelling of the earth caused by pressure from magma below. This pyroclastic flow actually has two major components, the visible ash cloud along with an avalanche of hot blocks from the disintegrating dome. The two types of flows leave different types of ash deposits, which geologists can identify long after an eruption.
Answer:
A physical change
Explanation:
You are wiping chalk particles from the board to the eraser which is just changing the location of the chalk particles, a physical change.
you're not changing the chalk into a new substance or causing a chemical reaction, which would be a chemical change.
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.
Energy Transformations Examples. An energy transformation is the change of energy from one form to another. Energy transformations occur everywhere every second of the day. There are many different forms of energy such as electrical, thermal, nuclear, mechanical, electromagnetic, sound, and chemical.