Physics help please..............

Which statements accurately describe Dmitri Mendeleev’s contributions to the development of the periodic table? Check all that a

Levart [38]

He produced the first orderly arrangement of known elements, he used patterns to predict undiscovered elements

6 0

3 years ago

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A 1200 kg car traveling east at 4.5 m/s crashes into the side of a 2100 kg truck that is not moving. During the collision, the v

zhenek [66]

Answer:

yyyggggggggggggggthhgggggyyyyy

Explanation:

yyygggggggggggg

4 0

3 years ago

Suppose a woman raises a 65 N object in 2m in 4 seconds.

Novosadov [1.4K]

Answer:

$\huge\boxed{\sf P.E = 130\ Joules}$

$\huge\boxed{\sf P = 32.5\ Watts}$

Explanation:

Given Data:

Weight = W = 65 N

Height = h = 2 m

Time = t = 4 secs

Required:

Power = P = ?

Work Done in the form of Potential Energy = P.E. = ?

Formula:

P.E. = Wh

P = P.E. / t

Solution:

P.E. = (65)(2)

P.E = 130 Joules

P = P.E. / t

P = 130 / 4

P = 32.5 Watts

$\rule[225]{225}{2}$

Hope this helped!

8 0

3 years ago

When a hot and cold object are placed in contact, the hot one loses energy. Does this violate energy conservation? Why or why no

blsea [12.9K]

Answer:

This does not violate the conservation of energy.

Explanation:

This does not violate the conservation of energy because the hot body gives energy in the form of heat to the colder body, this second absorbs energy. This will be the case until both bodies reach the same temperature, reaching thermal equilibrium and reducing the transfer of thermal energy. In this way the energy was only transferred from one body to another but the total energy of the system (body 1 plus body 2) will be the same as in the beginning, respecting the principle of conservation of energy or also called the first principle of thermodynamics .

The part of physics that studies these processes is in turn called heat transfer or heat transfer or thermal transfer. Heat transfer occurs whenever there is a thermal gradient or when two systems with different temperatures come into contact. The process persists until thermal equilibrium is reached, that is, until temperatures are equalized. When there is a temperature difference between two objects or regions close enough, the heat transfer cannot be stopped, it can only be slowed down.

8 0

3 years ago

Predict whether the changes in enthalpy, entropy, and free energy will be positive or negative for the melting of ice, and expla

BlackZzzverrR [31]

Melting of ice is an endothermic process, meaning that energy is absorbed. When ice spontaneously melts, ΔH (change in enthalpy) is "positive". ΔS (entropy change) is also positive, because, becoming a liquid, water molecules lose their fixed position in the ice crystal, and become more disorganized. ΔG (free energy of reaction) is negative when a reaction proceeds spontaneously, as it happens in this case. Ice spontaneously melts at temperatures higher than 0°C. However, liquid water also spontaneously freezes at temperatures below 0°C. Therefore the temperature is instrumental in determining which "melting" of ice, or "freezing" of water becomes spontaneous. The whole process is summarized in the Gibbs free energy equation:
ΔG = ΔH – TΔS

4 0

3 years ago