The horizontal force : f = k*N
k- coefficient of friction
k = f /N
N = m * g = 45 kg * 9.81 m/s² = 441.45 N
k = 25 N : 441.45 N = 0.057
Answer C) 0.057
C. The water cycle spreads water out evenly around the whole Earth
Answer:
Physical Properties of Sodium
Atomic number 11
Melting point 97.82°C (208.1°F)
Boiling point 881.4°C (1618°F)
Volume increase on melting 2.70%
Latent heat of fusion 27.0 cal/g
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Home Periodic table Elements Sodium
Sodium - Na
Chemical properties of sodium - Health effects of sodium - Environmental effects of sodium
Atomic number
11
Atomic mass
22.98977 g.mol -1
Electronegativity according to Pauling
0.9
Density
0.97 g.cm -3 at 20 °C
Melting point
97.5 °C
Boiling point
883 °C
Vanderwaals radius
0.196 nm
Ionic radius
0.095 (+1) nm
Isotopes
3
Electronic shell
[Ne] 3s1
Energy of first ionisation
495.7 kJ.mol -1
Option D) A drop of mercury is both a pure substance and and element.
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Answer:
The time it will take for the car to reach a velocity of 28 m/s is 7 seconds
Explanation:
The parameters of the car are;
The acceleration of the car, a = 4 m/s²
The final velocity of the car, v = 28 m/s
The initial velocity of the car, u = 0 m/s (The car starts from rest)
The kinematic equation that can be used for finding (the time) how long it will take for the car to reach a velocity of 28 m/s is given as follows;
v = u + a·t
Where;
v = The final velocity of the car, v = 28 m/s
u = The initial velocity of the car = 0 m/s
a = The acceleration of the car = 4 m/s²
t = =The time it will take for the car to reach a velocity of 28 m/s
Therefore, we get;
t = (v - u)/a
t = (28 m/s - 0 m/s)/(4 m/s²) = 7 s
The time it will take for the car to reach a velocity of 28 m/s, t = 7 seconds.