Lien is pushing a box across a table. She used a force of 100 N to get the box moving. Which force did she overcome to get the b

The heat required to raise the temperature of a substance by is represented by

where m stands for the mass of the substance and indicates the specific heat of the substance. In this situation, we possess and , the specific heat of water.
Consequently, we can ascertain the temperature rise :

Initially, the water's temperature was , so the end temperature should be

Thus, the water is expected to be vapor by now.

However, to give a more accurate statement, during the liquid to vapor transition, the heat added to the system is used to break molecular bonds instead of raising the system's temperature. The heat necessary for the phase change from liquid to vapor is expressed as

where denotes the latent heat of vaporization for water.
Nevertheless, the initial heat input of 50 KJ is less than this requirement, indicating there isn't sufficient heat to finish the liquid-vapor transition. Therefore, the water will remain in the liquid-vapor change phase at a temperature of (the temperature at which the phase change begins)

<span>First, apply Newton's second law of motion: F = ma. Force equals mass times acceleration. This law describes force as the product of mass multiplied by acceleration (which is different from velocity). As acceleration is the variation in velocity over time, we have force = (mass * velocity) / time, leading us to conclude that (mass * velocity) / time will equal momentum / time. Hence, we derive the equation mass * velocity = momentum. Momentum = mass * velocity. For the elephant, with a mass of 6300 kg and velocity of 0.11 m/s, Momentum = 6300 * 0.11, resulting in P = 693 kg (m/s). For the dolphin, having a mass of 50 kg and moving at 10.4 m/s, Momentum = 50 * 10.4, yielding P = 520 kg (m/s). Thus, the elephant has a greater momentum (P) due to its larger size.</span>

Part 1) Which metal will cool the fastest?
To determine this, we need to consider the heat flow rate formula, which indicates the speed at which a substance can gain or lose heat:

where:
denotes the heat exchanged
indicates the duration
k represents the thermal conductivity of the material
A is the area over which heat transfer takes place
shows the change in temperature
x is the thickness of the substance
It is evident that the heat flow rate is directly related to k, the thermal conductivity. Thus, a higher value of k means that the metal will cool more quickly.
Upon examining the thermal conductivity values for each metal, we observe:
- Aluminium: 237 W/(mK)
- Copper: 401 W/(mK)
- Gold: 314 W/(mK)
- Platinum: 69 W/(mK)
Consequently, copper has the highest heat flow rate, making it the metal that cools the fastest.

Part 2) Which sample of copper demonstrates the greatest increase in temperature
To address this part, we can examine how the heat exchanged Q correlates with temperature increase :

where m indicates the mass and Cs represents the specific heat capacity of the material. By rearranging the equation, we derive

As a result, it becomes clear that the temperature increase is inversely related to the mass m. Thus, the block exhibiting the highest temperature rise will be the one with the least mass, hence the right choice is A) 0.5 kg.

Flow rate calculations yield 220 cans, each with a volume of 0.355 l, leading to 78.1 l/min or 1.3 l/s or 0.0013 m³/s.

At Point 2:
A2 = 8 cm² = 0.0008 m²
V2 = Flow rate/A2 = 0.0013/0.0008 = 1.625 m/s
P1 = 152 kPa = 152000 Pa

At Point 1:
A1 = 2 cm² = 0.0002 m²
V1 = Flow rate/A1 = 0.0013/0.0002 = 6.5 m/s
P1 =?
Height = 1.35 m

Using Bernoulli’s principle;
P2 + 1/2 * V2² / density = P1 + 1/2 * V1² / density + density * gravitational acceleration * height
=> 152000 + 0.5 * (1.625)² * 1000 = P1 + 0.5 * (6.5)² * 1000 + (1000 * 9.81 * 1.35)
=> 153320.31 = P1 + 34368.5
=> P1 = 1533210.31 - 34368.5 = 118951.81 Pa = 118.95 kPa

Answer:

The work done, W = 19.6 J

Explanation:

It’s provided that

The mass of the block, m = 5 kg

The velocity of the block, v = 10 m/s

The coefficient of kinetic friction between the block and rough surface is 0.2

Distance traveled by the block, d = 2 m

As the block traverses the rough section, it loses energy equal to the work done by the kinetic energy.

W = 19.6 J

Thus, the change in kinetic energy of the block moving through the rough section is 19.6 J. Consequently, this is the required answer.