Density offers a convenient means of obtaining the mass of a body from its volume or vice versa; the mass is equal to the volume multiplied by the density (M = Vd), while the volume is equal to the mass divided by the density (V = M/d).
M = V d
M = 1.4 * 2 = 2.8 kg
A) The answer is 11.53 m/s
The final kinetic energy (KEf) is the sum of initial kinetic energy (KEi) and initial potential energy (PEi).
KEf = KEi + PEi
Kinetic energy depends on mass (m) and velocity (v)
KEf = 1/2 m * vf²
KEi = 1/2 m * vi²
Potential energy depends on mass (m), acceleration (a), and height (h):
PEi = m * a * h
So:
KEf = KEi + <span>PEi
</span>1/2 m * vf² = 1/2 m * vi² + m * a * h
..
Divide all sides by m:
1/2 vf² = 1/2 vi² + a * h
We know:
vi = 9.87 m/s
a = 9.8 m/s²
h = 1.81 m
1/2 vf² = 1/2 * 9.87² + 9.8 * 1.81
1/2 vf² = 48.71 + 17.74
1/2 vf² = 66.45
vf² = 66.45 * 2
vf² = 132.9
vf = √132.9
vf = 11.53 m/s
b) The answer is 6.78 m
The kinetic energy at the bottom (KE) is equal to the potential energy at the highest point (PE)
KE = PE
Kinetic energy depends on mass (m) and velocity (v)
KE = 1/2 m * v²
Potential energy depends on mass (m), acceleration (a), and height (h):
PE = m * a * h
KE = PE
1/2 m * v² = m * a * h
Divide both sides by m:
1/2 * v² = a * h
v = 11.53 m/s
a = 9.8 m/s²
h = ?
1/2 * 11.53² = 9.8 * h
1/2 * 132.94 = 9.8 * h
66.47 = 9.8 * h
h = 66.47 / 9.8
h = 6.78 m
Answer:
To convert m/sec into km/hr, multiply the number by 18 and then divide it by 5.
Explanation:
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The FREQUENCY of light remains unchanged once it leaves the source.
Answer:
T'=92.70°C
Explanation:
To find the temperature of the gas you use the equation for ideal gases:

V: volume = 3000cm^3 = 3L
P: pressure = 1250mmHg; 1 mmHg = 0.001315 atm
n: number of moles
R: ideal gas constant = 0.082 atm.L/mol.K
T: temperature = 27°C = 300.15K
For the given values you firs calculate the number n of moles:
![n=\frac{PV}{RT}=\frac{(1520[0.001315atm])(3L)}{(0.082\frac{atm.L}{mol.K})(300.15K)}=0.200moles](https://tex.z-dn.net/?f=n%3D%5Cfrac%7BPV%7D%7BRT%7D%3D%5Cfrac%7B%281520%5B0.001315atm%5D%29%283L%29%7D%7B%280.082%5Cfrac%7Batm.L%7D%7Bmol.K%7D%29%28300.15K%29%7D%3D0.200moles)
this values of moles must conserve when the other parameter change. Hence, you have V'=2L and P'=3atm. The new temperature is given by:

hence, T'=92.70°C