For each scenario below, indicate whether a chemical reaction or a nuclear reaction is occurring. a. When two compounds are combined heat is released.
b. A sample of galium-68 is reduced to one-half of its original amount in 68.3 minutes.
c. Radium-226 decays to radon-222.
d. A spark of energy is used to begin the combustion of methane gas.
e. Hydrogen nuclei are fused in the Sun to make helium atoms

In a wind tunnel the speed changes as the cross sectional area of the tunnel changes. if the speed in a 6' x 6' square test section is 100 mph, what was the speed upstream of the test section where the tunnel measured 20' x 20'? use conservation of mass and assume incompressible flow. conservation of mass requires that as the flow moves through a path or a duct the product of the density, velocity and cross sectional area must remain constant; i. e., that ova-constant. a model is being tested in a wind tunnel at a speed of 100 mph if the flow in the test section is at sea level standard conditions, what is the pressure at the model's stagnation point? (a) the tunnel speed is being measured by a pitot-static tube connected to a u- tube manometer. what is the reading on that manometer in inches of water? (b) at one point on the model a pressure of 2058 psf is measured. what is the local airspeed at that point?

The image below shows numerous volcanic mountains in the pacific northwest. what is the most likely cause of the volcanic and earthquake activity in this region?

Acar going 10 m/s starts accelerating at a rate of 3 m/s2 for 4 seconds calculate the final velocity of the car