Most metals have a specific build of electrons that makes them produce electricity better while other objects like plastic does not have electrons. Pretty much electrons are the things that help objects produce electricity well.

8 0

3 years ago

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A 45.0 kg girl is standing on a 159 kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat,

Ganezh [65]

Answer:

(a) $v_g_i=1.08\frac{m}{s}$

(b) $v_p_i=-0.3\frac{m}{s}$

Explanation:

According to the law of conservation of momentum:

$\Delta p=0\\p_i=p_f$

Initially, the girl and the plank are at rest. So, relative to the ice, we have:

$0=m_gv_g_i+m_pv_p_i\\v_p_i=-\frac{m_gv_g_i}{m_p_i}(1)$

(a) The velocity of the girl relative to the ice is:

$v_g_i=v_g_p+v_p_i(2)$

Here, $v_g_p$ is the velocity of the girl relative to the plank and $v_p_i$ is the velocity of the plank relative to the ice.

Replacing (1) in (2):

$v_g_i=v_g_p-\frac{m_gv_g_i}{m_p_i}\\v_g_i+\frac{m_gv_g_i}{m_p_i}=v_g_p\\v_g_i(1+\frac{m_g}{m_p})=v_g_p\\v_g_i=\frac{v_g_p}{1+\frac{m_g}{m_p}}\\v_g_i=\frac{1.38\frac{m}{s}}{1+\frac{45kg}{159kg}}\\v_g_i=1.08\frac{m}{s}$

(b) According to (2), the velocity of the plank relative to the surface of ice is:

$v_p_i=v_g_i-v_g_p\\v_p_i=1.08\frac{m}{s}-1.38\frac{m}{s}\\v_p_i=-0.3\frac{m}{s}$

The negative sing indicates that the plank is moving to the left.

3 0

3 years ago

What is the importance of discovering gravitational waves in science?

S_A_V [24]

<span>The importance of discovering gravitational waves are; one, we can measure the activity between two bodies in orbit in the universe, two, scientist can estimate the merging of two bodies in the universe every 15 minutes by using LIGO and three, we can know the behavior of other bodies that we did not know exist.</span>

4 0

3 years ago

A ball is dropped from the top of a building. When does the ball have the most potential energy?

exis [7]

Answer:

When it hits the ground

5 0

3 years ago