Answer:
The girl will move with constant velocity
Explanation:
If after a certain time t_0 the velocity of the girl is v_0 =gt_0 and the upward force on the girl due to rope is mg ,where g is gravitational acceleration. Then the girl will move down with the constant velocity v_0 .
The girl will move with constant velocity,as explained above.
The correct answer for this question is "Two-car length rule." While driving, the principle that you should be used to keep the appropriate distance between your vehicle and the vehicle in front of you is to follow the <span>Two-car length rule. This rule is to be followed for safety.</span>
Answer: <u><em>C. Steel</em></u>
Explanation: <em><u>When a sound wave travels through a solid body consisting</u></em>
<em><u /></em>
<em><u>of an elastic material, the velocity of the wave is relatively</u></em>
<em><u /></em>
<em><u>high. For instance, the velocity of a sound wave traveling</u></em>
<em><u /></em>
<em><u>through steel (which is almost perfectly elastic) is about</u></em>
<em><u /></em>
<em><u>5,060 meters per second. On the other hand, the velocity</u></em>
<em><u /></em>
<em><u>of a sound wave traveling through an inelastic solid is</u></em>
<em><u /></em>
<em><u>relatively low. So, for example, the velocity of a sound wave</u></em>
<em><u /></em>
<em><u>traveling through lead (which is inelastic) is approximately</u></em>
<em><u /></em>
<em><u>1,402 meters per second.</u></em>
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<h3>
Answer:</h3>
20 seconds
<h3>
Explanation:</h3>
<u>We are given</u>;
- Power of the engine as 400 watts
- Force as 100 N
- Distance the object is lifted up as 80 m
We are required to determine the time taken.
- We need to know that power is the rate of work done
Therefore;
But, work done = Force × distance
Work done = 100 N × 80 m
= 8000 Joules
- Since , Power = Work done ÷ time
Then, time = Work done ÷ Power
Thus;
Time = 8000 J ÷ 400 W
= 20 s
Therefore, the time taken by the engine to lift the object is 20 seconds
