<span>x=((12.3/100)m)cos[(1.26s^−1)t]
v= dx/dt = -</span><span>((12.3/100)*1.26)sin[(1.26s^−1)t]
v=</span>-((12.3/100)*1.26)sin[(1.26s^−1)t]=-((12.3/100)*1.26)sin[(1.26s^−1)*(0.815)]
v=<span>
<span>-0.13261622 m/s
</span></span>the object moving at 0.13 m/s <span>at time t=0.815 s</span>
Scalar quantities have only a magnitude. So the answer is scalar quantities.
Assuming that what you typed meant 20 seconds, rather than 2o seconds, the car is travelling at a velocity of 200 meters per second.
Answer: The control group is the part where you see what happens when you change a variable you want to study/examine. Basically, you need the control group because you need something to see what happens when you change something.
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I think the answer would be : A. more powerful
The shorter the electromagnetic wave is, the closer it is to the electromagnetic core, which make it more powerful
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