Physics, 27.07.2019 01:20 aaron3575

problem 1.5 a 250 g sample at 80°c is placed in a calorimeter containing 300 g of water. the mass of the aluminum calorimeter cup is 100 g. the initial temperature of the water and cup is 20.0°c, and the final temperature is 21.8°c. what is the specific heat of the sample?

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Answer from: chasadyyy

0.167 J/(g °C)

Explanation:

$m_{s}$ = mass of the sample = 250 g

$T_{si}$ = Initial temperature of sample = 80 °C

$m_{w}$ = mass of the water = 300 g

$m_{c}$ = mass of the cup = 100 g

$c_{w}$ = Specific heat of water = 4.186 J/(g °C)

$c_{s}$ = Specific heat of sample = ?

$c_{c}$ = Specific heat of aluminum cup = 0.9 J/(g °C)

$T_{wi}$ = Initial temperature of water = 20 °C

$T_{ci}$ = Initial temperature of aluminum cup = 20 °C

$T_{f}$ = Final temperature = 21.8 °C

Using conservation of heat

Heat lost by sample = Heat gained by water + Heat gained by cup

$m_{s} c_{s} (T_{si} - T_{f}) = m_{w} c_{w} (T_{f} - T_{wi}) + m_{c} c_{c} (T_{f} - T_{ci})$

$(250) c_{s} (80 - 21.8) = (300) (4.186) (21.8 - 20) + (100) (0.9) (21.8 - 20)$

$c_{s}$ = 0.167 J/(g °C)

Answer from: Quest

Answer8.0m;

Answer from: Quest

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

$f\alpha \frac{dp}{dt}$

⇒ $f= k \frac{dp}{dt}$

here k is the proportionality constant whose value is 1.

$f=\frac{dp}{dt}$

$f= \frac{d[mv]}{dt}$

$f= m\frac{dv}{dt} +v\frac{dm}{dt}$

$f=ma+v\frac{dm}{dt}$ [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.

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problem 1.5 a 250 g sample at 80°c is placed in a calorimeter containing 300 g of water. the...