Aparticle is moving along the x-axis so that its position at any time t is greater than and equal to 0 is given by x(t)=2te^-t?
a) find v(t).
b) find a(t).
c) at t=0, is the particle slowing down or speeding up? explain.
d) at what time(s), if any, does the particle change directions? justify your answer.
any would be greatly appreciated! !

A-of 75 cm by cm by 17.5 cm up. of is 2 kg a , in ,if it is in , kg/?

Does heating a metal wire increase or decrease its electrical resistance? why?

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.