Answer:
Explanation:
The high reached by a proyectile in an uniformly accelerated motion is given by:
The time that the rocket spends in the air is obtained for y = 0, since this is the time that the rocket travels before touching the ground. Recall that 
. Solving for t:
It is B. if i'm not mistaking
Answer:
0.25 m/s
Explanation:
From the law of conservation of momentum
Mu+ mu = Mv' + m v
M= mass of the astronaut = 80 kg
m= mass of the oxygen tank= 10 Kg
v= speedof the tank 2 m/s
u= initial velocity of the system= 0
If we substitute the values, we have
( 80× 0 )+(10×0)= [(80 x v )+ (10 x 2)]
0= 80v + 20
-20=80v
v= -0.25 m/s ( we have a negative value because the astronaut and the motion of the cylinder are in opposite direction)
Hence the velocity the astronaut start to move off into space is 0.25 m/s
Answer: Geothermal energy is produced by the heat of Earth's molten interior. This energy is harnessed to generate electricity when water is injected deep underground and returns as steam (or hot water, which is later converted to steam) to drive a turbine on an electric power generator.
Explanation: Hope this helps!
Answer:
c. expanded polyurethane
Explanation:
Thermal performance of a building fabric is measured in terms of heat loss and is expressed as U-value or R-value. U-value is the rate of heat transferred through a structure divided by the difference in temperature across the structure with a unit of measurement of W/m²K.You can calculate the U-value of a by getting the reciprocal of the sum of thermal resistances , R, making the building material.
If you have the value of R, then U=1/R
Material size R U
plywood 1" 1.25 0.8
Poured concrete 2" 0.99 1.010
Expanded polyurethane 1" 6.5 0.1538
Asbestos shingles 1" 0.03 33.33
The material with lowest U-value is expanded polyurethane
