Answer:
Cutting down trees instead of growing trees raises levels in the atmosphere, and Using clean energy sources instead of fossil fuels decreases the co2 levels in the atmosphere.
Explanation:
We know that the cutting down of tree and more use of fossil fuels increase the carbon dioxide in atmosphere and we can overcome it by using clean energy sources instead of fossil fuels.
Answer:
Science is supported by facts and processes.
Science involves observation and experimentation.
Science continually changes and is constantly updated.
Answer:
a) The mass flow rate through the nozzle is 0.27 kg/s.
b) The exit area of the nozzle is 23.6 cm².
Explanation:
a) The mass flow rate through the nozzle can be calculated with the following equation:

Where:
: is the initial velocity = 20 m/s
: is the inlet area of the nozzle = 60 cm²
: is the density of entrance = 2.21 kg/m³
Hence, the mass flow rate through the nozzle is 0.27 kg/s.
b) The exit area of the nozzle can be found with the Continuity equation:



Therefore, the exit area of the nozzle is 23.6 cm².
I hope it helps you!
Answer:
The false statement is in option 'd': The center of mass of an object must lie within the object.
Explanation:
Center of mass is a theoretical point in a system of particles where the whole mass of the system is assumed to be concentrated.
Mathematically the position vector of center of mass is defined as

where,
is the position vector of the mass dm.
As we can see for homogenous symmetrical objects such as a sphere,cube,disc the center of mass is located at the centroid of the shapes itself but in many shapes it is located outside the body also.
Examples of shapes in which center of mass is located outside the body:
1) Horseshoe shaped body.
2) A thin ring.
In many cases we can make shapes of bodies whose center of mass lies outside the body.