Answer:
D. Test a piece of treated iron and a piece of untreated iron under the same conditions.
Explanation:
A controlled experiment is defined as an experiment where the experimenter or the researcher tries to test or experiment his result by changing one variable at a time and keeping the other factors under the same conditions and sees how it effects the result.
The factors which can be changed in an experiment is called its variables.
In the context, testing a piece of treated iron as well as a untreated piece of iron under the same working conditions forms a controlled experiment.
Answer:
By Gaining Electrons
Explanation:
A nuetral atom is negative when it gains electrons, and it can be positive when it loses electrons.
Answer:
588 J
Explanation:
PE (potential energy) = (mass) x (gravity) x (height)
mass = 12 kg
gravity = 9.8m/s^2
height = 5 m
PE = (12) x (9.8) x (5) = 588 J (Joules)
Answer:
27.22 F.
Explanation:
T ( t ) = T₀ + ( T₁ - T₀)
T ( t ) = 41 , T₀ = 0 , T₁ = 140 , t = 15
Put these values in the equation above
41 = ( 140 - 0 ) e^{-15k}
41/140 = e ^{-15k}
(41/140)^{1/3} = e ^{-5k}
Let after 20 minutes temperature becomes T
T = 0 + 140 e^{-k20}
T / 41 = e^{-5k }
= (41/140)^{1/3}
T = 41 X (41/140)^{1/3}
= 27.22 F.
Answer:
366 m
Explanation:
u = 90 km/h = 25 m/s,
theta = 5 degree
acceleration, a = g Sin theta = 9.8 x Sin 5 = 0.854 m/s^2
The final velocity os zero and let the braking distance be s.
Use third equation of motion
v^2 = u^2 - 2 a s
0 = 25 x 25 - 2 x 0.854 x s
s = 366 m
