The specific gravity is the ratio of the substances density to that of water at 4 degrees Celsius. With this, it is conclusive that the density of iron is 7.87 g/cm³. The volume occupied by the iron is the quotient when mass is divided by density,
V = m / D = (7 g) / (7.87 g/cm³) = 0.89 cm³
Therefore, 7 grams of iron occupies approximately 0.89 cm³.
4.85 x 104.
This is the right answer.
Answer: 68852 millijoules = 16.46 calories
Explanation:
Given;
Convert 68852 millijoules to calories.
1 calorie = 4.184J = 4184millijoules
Therefore,
1 millijoule = 1/4184 calories
68852 millijoule = 68852 × 1/4184 calories
= 16.46 calories
b. the forces of attraction among them limit their motion.
Answer:
Δt'/ T% = 90.3%
Explanation:
Simple harmonic movement is described by the expression
x = A cos (wt)
we find the time for the two points of motion
x = - 0.3 A
-0.3 A = A cos (w t₁)
w t₁ = cos -1 (-0.3)
remember that angles are in radians
w t₁ = 1.875 rad
x = 0.3 A
0.3 A = A cos w t₂
w t₂ = cos -1 (0.3)
w t₂ = 1,266 rad
Now let's calculate the time of a complete period
x= -A
w t₃ = cos⁻¹ (-1)
w t₃ = π rad
this angle for the forward movement and the same time for the return movement in the oscillation to the same point, which is the definition of period
T = 2 t₃
T = 2π / w s
now we can calculate the fraction of time in the given time interval
Δt / T = (t₁ -t₂) / T
Δt / T = (1,875 - 1,266) / 2pi
Δt / T = 0.0969
This is the fraction for when the mass is from 0 to 0.3, for regions of oscillation of greater amplitude the fraction is
Δt'/ T = 1 - 0.0969
Δt '/ T = 0.903
Δt'/ T% = 90.3%