Answer:
Different surfaces
<h3>You can see that dull surfaces are good absorbers and emitters of infrared radiation. Shiny surfaces are poor absorbers and emitters (but they are good reflectors of infrared radiation</h3>
 
        
             
        
        
        
Answer:
47.4 m
Explanation:
When an object is thrown upward, it rises up, it reaches its maximum height, and then it goes down. The time at which it reaches its maximum height is half the total time of flight.
In this case, the time of flight is 6.22 s, so the time the ball takes to reach the maximum height is

Now we consider only the downward motion of the ball: it is a free fall motion, so we can find the vertical displacement by using the suvat equation

where
s is the vertical displacement
u = 0 is the initial velocity
t = 3.11 s is the time
 is the acceleration of gravity (taking downward as positive direction)
 is the acceleration of gravity (taking downward as positive direction)
Solving the  formula, we find

 
        
             
        
        
        
Answer:
R=m*g-∀fl*g*l3
Explanation:
<em>An iron block of density rhoFe and of volume l 3 is immersed in a fluid of density rhofluid. The block hangs from a scale which reads W as the weight. The top of the block is a height h below the surface of the fluid. The correct equation for the reading of the scale is</em>
From Archimedes' principle we know that a body when immersed in a fluid, fully or partially, experiences an the upward buoyant force equal to the weight of the fluid displaced. As the body is fully submerged in water, volume of water displaced  
density of iron =mass/ volume
rho=m/l3
mass=rhol3
weight fluid=rhofluid*g*Volume
weight of fluid=rhofluid*g*l3
F=∀fl*g*l3
Downward force is weight of iron
w=m*g
Reading on the spring scale
R=w-F
R=m*g-∀fl*g*l3
m=mass of iron
g=acceleration due to ravity
rhfld=density of fluid
l3=volume of fluid displaced
 
        
             
        
        
        
Answer:
C) Use a battery with more voltage.
Explanation:
The equation for the magnetic field around a coil is given by,
B = μ₀NI
where, 
B = Magnetic flux density
μ₀ = permeability
N = number of turns per meter
I = Current in the wire
So when using a higher voltage battery, more current passes through the battery as resistance of the wire remains the same.