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3 years ago

Which one of the following statements is true?

1 answer:

3 0

B. Because chemical changes (for example, burning turning something into ashes) can change it's appearance while physical changes (for example, crumpling a piece of paper) can aswell.

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Electromagnetic waves differ from other types of waves because they are

nikklg [1K]

I think it is D because u think of space and Electromagnetic Waves Travel Through Space Moving All Kinds of Particles From The Sun With It Which Creates The Northern and Southern Lights In The Poles :-)

8 0

3 years ago

A 10 kg monkey climbs up a massless rope that runs over a frictionless tree limb and back down to a 15 kg package on the ground.

pshichka [43]

Answer:

A. 4,9 m/s2

B. 2,0 m/s2

C. 120 N

Explanation:

In the image, 1 is going to represent the monkey and 2 is going to be the package. Let a_mín be the minimum acceleration that the monkey should have in the upward direction, so the package is barely lifted. Apply Newton’s second law of motion:

$\sum F_y=m_1*a_m_i_n = T-m_1*g$

If the package is barely lifted, that means that T=m_2*g; then:

$\sum F_y =m_1*a_m_i_n=m_2*g-m_1*g$

Solving the equation for a_mín, we have:

$a_m_i_n=((m_2-m_1)/m_1)*g = ((15kg-10kg)/10kg)*9,8 m/s^2 =4,9 m/s^2$

Once the monkey stops its climb and holds onto the rope, we set the equation of Newton’s second law as it follows:

For the monkey: $\sum F_y = m_1*a \rightarrow T-m_1*g=m_1*a$

For the package: $\sum F_y = m_2*a \rightarrow m_2*g - T = m_2*a$

The acceleration a is the same for both monkey and package, but have opposite directions, this means that when the monkey accelerates upwards, the package does it downwards and vice versa. Therefore, the acceleration a on the equation for the package is negative; however, if we invert the signs on the sum of forces, it has the same effect. To be clearer:

For the package: $\sum F_y = -m_2*a \rightarrow T-m2*g=-m_2*a \rightarrow m_2*g -T=m_2 *a$

We have two unknowns and two equations, so we can proceed. We can match both tensions and have:

$m_1*a+m_1*g=m_2*g-m_2*a$

Solving a, we have

$(m_1+m_2)*a =(m_2 - m1)*g\\\\a=((m_2-m_1)/(m_1+m_2))*g \rightarrow a=((15kg-10kg)/(10kg+15kg))*9,8 m/s^2\\\\a= 2,0 m/s^2$

We can then replace this value of a in one for the sums of force and find the tension T:

$T = m_1*a+m_1*g \rightarrow T=m_1*(a+g)\\\\T = 10kg*(2,0 m/s^2+9,8 m/s^2) \\\\T = 120 N$

5 0

3 years ago

According to the kinetic molecular therory, the pressure of a gas in a container will increase if the

Masja [62]

According to the kinetic molecular theory, the pressure of a gas in a container will increase if the number of collisions with the container wall increases.

<u>Explanation:</u>

Keeping the volume of the vessel constant, if we increase the amount of gas in it; the pressure will increase. This is because when the number of gas particles increases in that limited volume, they hit the walls of the container with more energy and hence, the overall pressure of the gas increases.

If we decrease the amount of gas in the vessel or increase the volume for the same amount of gas, the pressure decreases. As the pressure inside the vessel depends upon the gas supplied in the container.

5 0

3 years ago

Is lateral shift or lateral displacement same ?

xxMikexx [17]

Answer:

When a ray of light passes through a glass slab of a certain thickness, the ray gets displaced or shifted from the original path. This is called lateral shift/displacement.

Explanation:

7 0

3 years ago

A 66.0−kg short-track ice skater is racing at a speed of 10.0 m/s when he falls down and slides across the ice into a padded wal

dexar [7]

Answer:

3300J

Explanation:

Work done is the energy that is lost by the skater

Formula for workdone = 1/2*mV^2

m = 66kg

V = 10m/s

Work done = 1/2 * 66 * 10^2

= 3300J

7 0

3 years ago