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3 years ago

A skier is gliding down a slope at a constant speed. what energy transformation is taking place?

1 answer:

7 0

In this process, gravitational potential energy is converting into heat/thermal energy.

In fact, the skier starts at a certain height h, so it has gravitational potential energy equal to
$U=mgh$
as he slides down, he loses this energy. However, the problem says that the speed of the skier remains constant during the motion, so this energy is not converting into kinetic energy, which remains constant. The only possibility is that a frictional force between the skier and the ice is acting on the skier. When the friction acts, the energy of the skier is converted into motion of the molecules of the ice, heating it, so into thermal energy.

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An object has a position given by the radius vector r = [2.0 m + (3.00 m/s)t](i)+ [3.0 m - (2.00 m/s^2)t^2](j). Here (i) and (j)

jenyasd209 [6]

Answer:

The speed of the object is ( $3i - 4.00tj$ )m/s

The magnitude of the acceleration is 4.00m/s²

Explanation:

Given - position vector;

r = (2.0 + 3.00t)i + (3.0 - 2.00t²)j -------------------(i)

To get the speed vector ( $v$ ), take the first derivative of equation (i) with respect to time t as follows;

$v$ = $\frac{dr}{dt}$

$v$ = $\frac{d[(2.0 + 3.00t)i + (3.0 - 2.00t^2)j] }{dt}$

$v$ = $3i - 4.00tj$ ------------------------(ii)

To get the acceleration vector ( $a$ ), take the first derivative of the speed vector in equation(ii) as follows;

$a = \frac{dv}{dt}$

$a = \frac{d(3i - 4.00tj)}{dt}$

$a = -4.00$ j

The magnitude of the acceleration |a| is therefore given by

|a| = |-4.00|

|a| = 4.00 m/s²

In conclusion;

the speed of the object is ( $3i - 4.00tj$ )m/s

the magnitude of the acceleration is 4.00m/s²

3 0

3 years ago

Suppose we have three hypothetical atomic nuclei: A, B, and C. Nucleus A has 7 protons and 7 neutrons. Nucleus B has 5 protons a

alina1380 [7]

Answer:

Nucleus A with 7 protons and 7 neutrons and Nucleus C with 7 protons and 5 neutrons are isotopes of the same elements

Explanation:

Isotopes are elements that have the same atomic structure but different molecular structure. An atom that has the same atomic number but different mass number are known to be isotopes.

The proton of an atom is the same as its atomic number while the sum of the proton and neutron is equal to its mass number.

According to the question, nuclei that has the same number of proton are isotopes of the same element. Therefore nuclei A and C with 7 protons each are isotopes of the same element since they have the same atomic number i.e number of proton = atomic number.

Their atomic masses of nuclei A and C are 14 and 12 respectively

3 0

3 years ago

En el País Vasco los deportistas rurales levantan enormes piedras hasta su hombro. En un concurso , Jose levanta una piedra de 2

Mama L [17]

Answer:

Txomin lifted the stone with greater mass. (Txomin levantó la roca con mayor fuerza).

Explanation:

The sportsman that lifts the stone with a greater mass needs a higher force (El deportista que levanta la piedra con mayor masa necesita una mayor fuerza):

José

$F = (200\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)$

$F = 1961.4\,N$

Txomin

$F = (220\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)$

$F = 2157.54\,N$

Txomin lifted the stone with greater mass. (Txomin levantó la roca con mayor fuerza).

5 0

3 years ago

The rate at which the earth's surface loses heat and keeps earth temperature at which living things can survive

agasfer [191]

<span>I believe it's insulation.</span>

5 0

3 years ago

A ball is dropped from the top of the building.it initially moves at 4.0 m/s after 0.5 seconds it moves at 3.8m/s what force is

Ivahew [28]

The correct answer is

Air resistance

In fact, when a ball is in free fall, there are two forces acting on it:

- its weight (force of gravity), acting downward

- the air resistance, acting upward

The effect of the weight is to accelerate the ball, because its direction is the same as the direction of motion of the ball, while the effect of the air resistance is to slow down the ball, because its direction is opposite to that of the motion.

6 0

3 years ago