1) 0N... friction opposes the motion of an object, since the block is at rest there is no motion thus no friction
2) F=ma
= (5.5kg)(30m/s)
=165 N
Answer:

<em>The potential environmental impacts associated with solar power—land use and habitat loss, water use, and the use of hazardous materials in manufacturing—can vary greatly depending on the technology, which includes two broad categories: photovoltaic (PV) solar cells or concentrating solar thermal plants (CSP).</em>
Explanation:
I just answer the second question
This implies that stopping distance and impact force grow as a function of speed. The best ways to improve manoeuvrability and lessen crash severity are to drive at an appropriate pace and to slow down as soon as you spot dangers in front of you.
Keep in mind that stopping distance increases with speed; at 50 mph, it is four times longer than at 25 mph, and at 75 mph, the force of impact is nine times greater.
<h3>What is the impact of speed on kinetic energy ?</h3>
When your car expends or absorbs energy to speed up or slow down, you may feel a pull or a jolt, called impulse. Impulse increases as the energy or force increases, and increases as the duration of the force decreases. You'll feel a harder jolt if you speed up or slow down suddenly.
- Consider: coming to a stop from 60 mph in ten seconds doesn't hurt you or your vehicle because the force of this event is spread out over a long time. But if you hit a wall and come to a stop in just half a second, you'll feel twenty times the impulse, causing severe damage.
Learn more about Kinetic energy here:
brainly.com/question/25959744
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Answer:
34883.7
Explanation:
Primero hay que convertir las dos unidades a la misma unidad-cm-
3km- 300000 cm
86mm- 8.6mm
Después hay que dividir
300000/8.6= 34883.7209302 ~ 34883.7
The answer that is got 8.7 . I got that because if you divide 200 by 23 you get <span>8.69565217391 and if you round that you get 8.7</span>