Answer:
The melting and boiling point of water in Fahrenheit scale is divided into 180 equal intervals, that means each division denoting 1°F.
division means their melting and boiling point is divided into 180 equal intervals that means each division indicates 1 degree F.
Answer:
The child will take 5.952 seconds to travel from the top of the hill to the bottom.
Explanation:
Given that the child accelerates uniformly and that both initial (
) and final speeds (
), measured in meters per second, and acceleration (
), measured in meters per square second, are known, we proceed to use the following kinematic equation to determine the time taken to travel from the top of the hill to the bottom (
), measured in seconds, is:
(1)
If we know that
,
and
, then the time taken is:

The child will take 5.952 seconds to travel from the top of the hill to the bottom.
Answer:
A) 3.13 m/s
B) 5.34 N
C) W = 26.9 J
Explanation:
We are told that the position as a function of time is given by;
x(t) = αt² + βt³
Where;
α = 0.210 m/s² and β = 2.04×10^(−2) m/s³ = 0.0204 m/s³
Thus;
x(t) = 0.21t² + 0.0204t³
A) Velocity is gotten from the derivative of the displacement.
Thus;
v(t) = x'(t) = 2(0.21t) + 3(0.0204t²)
v(t) = 0.42t + 0.0612t²
v(4.5) = 0.42(4.5) + 0.0612(4.5)²
v(4.5) = 3.1293 m/s ≈ 3.13 m/s
B) acceleration is gotten from the derivative of the velocity
a(t) = v'(t) = 0.42 + 2(0.0612t)
a(4.5) = 0.42 + 2(0.0612 × 4.5)
a(4.5) = 0.9708 m/s²
Force = ma = 5.5 × 0.9708
F = 5.3394 N ≈ 5.34 N
C) Since no friction, work done is kinetic energy.
Thus;
W = ½mv²
W = ½ × 5.5 × 3.1293²
W = 26.9 J
Coal is burned to get energy. By burning coal, green houses gases like carbon dioxide, nitrogen oxides and suphur oxides are produced.
Rest of the energy sources given in the option are clean energies.
Answer is A.