1).
Time = (distance) / (speed)
Time = (1000 meters) / (331 m/s)
<em>Time = 3.02 seconds</em>
2).
Acceleration = (change in speed) / (time for the change)
Change in speed = (second speed) - (first speed)
Change in speed = (50 m/s) - (20 m/s) = 30 m/s
Acceleration = (30 m/s) / (5 seconds)
<em>Acceleration = 6 m/s²</em>
Work done to lift the rock is 6174 Joule.
To find the answer, we need to know about the work done.
<h3>What's the work done?</h3>
Mathematically, work done = force × distance
<h3>What's the gravitational force acts on the stone here?</h3>
The gravitational force on the stone = mg
= 210× 9.8= 2058N
<h3>What's the work done to lift the stone?</h3>
Work done= 2058× 3
= 6174 Joule
Thus, we can conclude that the work done to lift the stone is 6174 Joule.
Learn more about the work done here:
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Σ/ε
σ = F/A
ε = ΔL/L
F = force
A = area
L = lenght
ΔL = |old lenght - new lenght|
I think the answer is c but I'm not sure
The answer would be B. Freezing water breaks apart a rock