If an object is moving up, is it considered to have a positive or negative velocity?

Jack travelled 360 km at an average speed of 80 km/h. Elaine

diamong [38]

Answer:

Average speed of Elain = 60 km/h

Explanation:

Total Distance covered by Jack = 360km

Average Speed of Jack = 80 km/h

Time taken by Jack to complete his journey = Distance / Average speed = 360 km / 80 km/h

Time taken by Jack to complete his journey = 4.5 hours

As it is given the both Jack and Elain travelled the same amount of distance:

Total distance travelled by Elain = 360 km

It is given that Elain took 1.5 hourse more than Jack to cover the distance, so Time taken by Elain to cover the distance is = 4.5 hours + 1.5 hours = 6 hours

Average speed of Elain = Distance/ time = 360 km / 6 hours

Average speed of Elain = 60 km/h

3 0

2 years ago

A physics major is cooking breakfast when he notices that the frictional force between the steel spatula and the Teflon frying p

Semenov [28]

Answer:

$f_n=3.75N$

Explanation:

From the question we are told that:

Frictional force $F=0.150N$

Coefficient of kinetic friction $\mu=0.04$

Generally the equation for Normal for is mathematically given by

$f_n=\frac{F}{\mu}$

Therefore

$f_n=\frac{0.150}{0.04}$

$f_n=3.75N$

5 0

2 years ago

The planet Saturn has a mass that is 95 times Earth's mass and a radius that is 9.4 times Earth's radius. What is the accelerati

ziro4ka [17]

Answer:

10.55111 m/s²

Explanation:

M = Mass of Saturn = $95\times 5.972\times 10^{24}\ kg$

r = Radius of Saturn = $9.4\times 6.371\times 10^6\ m$

G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²

Acceleration due to gravity is given by

$g=\dfrac{GM}{r^2}\\\Rightarrow g=\dfrac{6.67\times 10^{-11}\times 95\times 5.972\times 10^{24}}{(9.4\times 6.371\times 10^6)^2}\\\Rightarrow g=10.55111\ m/s^2$

The acceleration due to gravity on Saturn is 10.55111 m/s²

4 0

2 years ago

‼️‼️ Please help, urgent ‼️‼️ (check photo)

Alex787 [66]

Answer: The force constant k is 10600 kg/s^2

Step by step:

Use the law of energy conservation. When the elevator hits the spring, it has a certain kinetic and a potential energy. When the elevator reaches the point of still stand the kinetic and potential energies have been transformed to work performed by the elevator in the form of friction (brake clamp) and loading the spring.

Let us define the vertical height axis as having two points: h=2m at the point of elevator hitting the spring, and h=0m at the point of stopping.

The total energy at the point h=2m is:

$E_{tot}=E_{kin}+E_{pot}\\E_{tot}= \frac{1}{2}mv^2+mg\Delta h = \frac{1}{2}2000 kg 4^2\frac{m^2}{s^2}+2000kg\, 9.8\frac{m}{s^2}2m=55200\,kg\frac{m^2}{s^2}$

The total energy at the point h=0m is:

$E_{tot}=E_{kin}+E_{pot}+Work=0+0+ Work\\E_{tot} =F_{friction}\Delta h+\frac{1}{2}k (\Delta h)^2=17000N\cdot 2m+\frac{1}{2}k\cdot 2^2 m^2$

The two Energy values are to be equal (by law of energy conservation), which allows us to determine the only unknown, namely the force constant k:

$17000N\cdot 2m+\frac{1}{2}k\cdot 2^2 m^2 = 55200 \,kg\frac{m^2}{s^2}\\k = \frac{55200-34000}{2}\,\frac{kg}{s^2}=10600\frac{kg}{s^2}$

5 0

3 years ago

Humans are a part of the Earth system. List at least three examples of how you, in particular, influence one or more of Earth’s

Naily [24]

Answer:

True, The humans have modified their environment the ecological system

Explanation:

Human is a part of the earth system and they are included in the ecological system that in particular is concerned with the provision of the feedback mechanism and cyclic flow of the system of energy such as the atmosphere, cryosphere, and the biosphere and the hydrosphere.

The human has already and influences the earth's physical system alike that of the atmospheric system in terms of the climate changes and the global warming that is taking place at a massive scale.

They are influencing the soil and land systems in terms of the depletion resources and the disturbing the hydrological cycles on earth that further influence the amounts of rainfall patterns.

The three examples given above are those of the use of the natural resources and thereby depletion of resources which are needed to sustain the functioning of the planet and various fields of the economics and the geology and that of the socio systems are also impacted and these forms the earth's major sphere of life.

8 0

3 years ago