40 POINTS

A crate of mass 9.2 kg is pulled up a rough incline with an initial speed of 1.58 m/s. The pulling force is 110 N parallel to th

kari74 [83]

Given that,

Mass = 9.2 kg

Force = 110 N

Angle = 20.2°

Distance = 5.10 m

Speed = 1.58 m/s

(A). We need to calculate the work done by the gravitational force

Using formula of work done

$W_{g}=mgd\sin\theta$

Where, w = work

m = mass

g = acceleration due to gravity

d = distance

Put the value into the formula

$W_{g}=9.2\times(-9.8)\times5.10\sin20.2$

$W_{g}=-158.8\ J$

(B). We need to calculate the increase in internal energy of the crate-incline system owing to friction

Using formula of potential energy

$\Delta U=-W$

Put the value into the formula

$\Delta U=-(-158.8)\ J$

$\Delta U=158.8\ J$

(C). We need to calculate the work done by 100 N force on the crate

Using formula of work done

$W=F\times d$

Put the value into the formula

$W=100\times5.10$

$W=510\ J$

We need to calculate the work done by frictional force

Using formula of work done

$W=-f\times d$

$W=-\mu mg\cos\theta\times d$

Put the value into the formula

$W=-0.4\times9.2\times9.8\cos20.2\times5.10$

$W=-172.5\ J$

We need to calculate the change in kinetic energy of the crate

Using formula for change in kinetic energy

$\Delta k=W_{g}+W_{f}+W_{F}$

Put the value into the formula

$\Delta k=-158.8-172.5+510$

$\Delta k=178.7\ J$

(E). We need to calculate the speed of the crate after being pulled 5.00m

Using formula of change in kinetic energy

$\Delta k=\dfrac{1}{2}m(v_{2}^2-v_{1}^{2})$

$v_{2}^2=\dfrac{2\times\Delta k}{m}+v_{1}^2$

Put the value into the formula

$v_{2}^2=\dfrac{2\times178.7}{9.2}+1.58$

$v_{2}=\sqrt{\dfrac{2\times178.7}{9.2}+1.58}$

$v_{2}=6.35\ m/s$

Hence, (A). The work done by the gravitational force is -158.8 J.

(B). The increase in internal energy of the crate-incline system owing to friction is 158.8 J.

(C). The work done by 100 N force on the crate is 510 J.

(D). The change in kinetic energy of the crate is 178.7 J.

(E). The speed of the crate after being pulled 5.00m is 6.35 m/s

8 0

3 years ago

Which term is defined by the force that moving, charged particles exert on one another?

Lisa [10]

Answer:

Electromagnetic force

Explanation:

There are four fundamental forces in nature:

- Gravity: it is the force that is exerted between any objects with mass. It is the weakest of all forces, so it is only relevant at planetary scales. It is always attractive, and it has an infinite range.

- Electromagnetic force: it is the force exerted between charged objects and between magnets (it is responsible for electric fields and magnetic fields). It is the 2nd strongest force, and it is the force that holds atoms in a molecule together. It can be attractive or repulsive, and it has an infinite range.

- Strong nuclear force: it is the strongest of all forces. It is responsible for holding the nucleons together inside the nucleus, and it is attractive. It has a very limited range ( $10^{-15}m$ ), so it is relevant only at very small scales

- Weak nuclear force: it is the force responsible for radioactive decays and neutrino interactions. It also has a very short range ( $10^{-18} m$

Looking at all these definitions, we see that the term that defines the force that acts between charged particles is the electromagnetic force.

7 0

3 years ago

Explain the concept behind the multiverse. 2. what did astronomer edwin hubble discover in 1929? 3. explain what the two teams o

lozanna [386]

PART A)
1) The Multiverse is a system of multiple parallel Universes, in which our Universe is only one of the possible configurations.

2) Hubble in 1929 discovered, looking at distant galaxies, that they are moving away from us with a speed greater than expected as if they are on a moving pavement. This led to the idea of expanding Universe.

3) In the 1990s it was discovered that the Universe is expanding not at a decelerating rate, but, on the contrary, at an accelerating rate. The question that arose is: what is accelerating the expansion of the Universe?

4) The amount of dark energy that is making the Universe expansion to accelerate, also know as repulsive gravity, that is needed to explain what we see, is very small, therefore it must come out from laws of physics, but no one has yet found how. Although this amount is so small to be called a detail, Greene thinks it is important because it could prove the existence of other Universes.

5) The idea behind the string theory is that every sub-atomic particle is made of tiny vibrating strings and the way they vibrate determines what kind of particle is created. In order to make this theory to work, we need to allow the possibility of dimensions other than the four (3 of space + 1 of time) we experience every day.

6) Greene says that the Big Bang was fueled by an explosion, called inflation. Since this fuel is very efficient, it could have powered not only our Universe but also other parallel Universes, with different characteristics from ours. A forever expanding Universe will lead to galaxies so far away from each other not to be visible anymore because the light departing from them could not reach us anymore. Therefore in the future, the sky could be totally black, and future astronomers could believe that the Universe is nothing else than the planet they live in.

PART B)
1) The problem of living in our Universe is that we can only see it from inside and we cannot have the big picture of how things work, we can only see things that are inside our observational limits.

2) A flat geometry means that if you draw a triangle the sum of the angles is always 180°, exactly like in the Euclidean plane. Also, <span>that two parallel lines remain parallel forever, therefore light travels in a straight line.</span>

3) Gravity is an attractive force, therefore a galaxy can be redirected from its original direction when passing close to another galaxy. In some cases, the two galaxies start rotating around each other and at the end they merge, forming a new galaxy.

8 0

3 years ago

Read 2 more answers

A cleaner pushes a 4.50-kg laundry cart in such a way that the net external force on it is 60.0 N. Calculate the magnitude of it

liq [111]

Answer:

The acceleration of the laundry cart is 13.3 m/s²

Explanation:

Hi there!

According to Newton's second law, the sum of all forces acting on an object in a given direction is equal to the mass of the object times its acceleration in that direction:

∑F = m · a

Where:

∑F = net force acting on the cart.

m = mass of the cart.

a = acceleration.

Then, solving this equation for the acceleration:

∑F / m = a

60.0 N / 4.50 kg = a

a = 13.3 m/s²

The acceleration of the laundry cart is 13.3 m/s²

5 0

3 years ago

Read 2 more answers

What simple machine is a Window Screen

Alika [10]

AnswER PIZZA?

Explanation:

5 0

3 years ago