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4 years ago

Scientists know how groups of animals changed over time by studying information contained in the ______________.

2 answers:

5 0

The answer would be ROCKS because rocks contain fossils and the fossils can reveal a lot of the past life of extinct animals.

Arisa [49]4 years ago

3 0

Fossil succession is the blank answer.

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A speck of dust with mass 12 mg and electric charge 10 μC is released from rest in a uniform electric field of magnitude 850 N/C

Marta_Voda [28]

Answer:

$a=708.3m/s^2$

Explanation:

The force experimented by a charge q in a uniform electric field E is F=qE.

Newton's 2nd Law tells us that the relation between acceleration a a mass m experiments when a force F is applied to it is F=ma.

Combining these equations we have am=qE, and since we want the acceleration of the speck of dust, we substitute our values:

$a=\frac{qE}{m}=\frac{(10\times10^{-6}C)(850N/C)}{12\times10^{-6}Kg}=708.3m/s^2$

4 0

3 years ago

Does an object in rest have potential energy

kenny6666 [7]

Yes, of course! by it's definition the potential energy is an energy that particle have in order to obtain kinetic energy. Or simply an energy to make some movement.

4 0

4 years ago

A firework is designed so that when it is fired directly upwards, it explodes and splits into three equal-massed parts at its pe

Arturiano [62]

Answer:

the third piece landed $2\,\sqrt{2}$ meters in a direction 45 degrees from the observer's right towards the front

Explanation:

Due to conservation of momentum, the momentum of the third piece must add to the other two momenta in vector from to render zero (initial momentum of the firework on a plane parallel to ground. Therefore the momentum components of the third piece must have a component to the right equal in magnitude to the momentum of the piece that traveled to the left, and a momentum component pointing to the front of the observer of equal magnitude to that of the piece that traveled behind the observer. Then the direction of the third momentum must be at 45 degrees from the observer's right towards the observer's front.

Also, the magnitude of a momentum vector of such components, is given by the Pythagorean theorem. Recall also that the magnitudes of the momentum vectors of the first two pieces must be equal since they traveled equal distances.

$|P_3|=\sqrt{P_1^2+P_2^2} \\|P_3|=\sqrt{P^2+P^2}\\|P_3|=\sqrt{2P^2}\\|P_3|=P\sqrt{2}$

Then the distance traveled by the third piece must also keep this proportionality:

$D_3=\sqrt{2} \,\,D\\D_3=\sqrt{2} \,*\,2\,\,meters\\D_3=2\,\sqrt{2} \,\,meters$

4 0

3 years ago

A rod of length L is hinged at one end. The moment of inertia as the rod rotates around that hinge is ML2 /3. Suppose a 2.00-m r

Stels [109]

To solve this problem we will apply the concepts related to the moment of inertia and Torque, the latter both its translational and rotational expression.

According to the information given the moment of inertia of the body would be

$I = \frac{1}{3} mL^2$

Replacing we have

$I = \frac{1}{3} (3kg)(2m)^2$

$I = 4 kg * m^2$

Now the translational torque would be the product between the force applied (Its own Weight) and the distance (Its center of mass at the middle)

$\tau = F*r$

$\tau = mg (\frac{L}{2})$

$\tau = (3)(9.8)(\frac{2}{2})$

$\tau = 29.4N\cdot m$

Now the rotational torque is defined as the product between the moment of inertia and the angular acceleration, then,

$\tau = I\alpha \rightarrow \alpha = \frac{\tau}{I}$

Replacing,

$\alpha = \frac{29.4}{4}$

$\alpha =7.35 rad / s^2$

Therefore the angular acceleration is $7.35rad/s^2$

4 0

3 years ago

What is a moon node? have a great day

RideAnS [48]

Answer:

lunar node in other words is either of the two orbital nodes of the Moon, that is, the two points at which the orbit of the Moon intersects the ecliptic. The ascending node is where the Moon moves into the northern ecliptic hemisphere, while the descending node is where the Moon enters the southern ecliptic hemisphere

3 0

3 years ago

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