2. Sa se calculeze masa unui corp care are greutatea de 45 N. 3. O forță de 30 N ii produce unui resort, acționând asupra lui, o deformare de 6 cm. Sa
se calculeze constanta elastica a resortului.
4. Care va fi deformarea unui resort sub acțiunea unei forte de 5N, daca la acțiunea unei
forte de 15N, deformarea a fost de 6 cm?

It is d, all the other ones say incorrect answer .

If its history of, then b) because a) implies only present day (now)

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j

Answerapplying a direct current to a non magnetic material in order to create a electromagnetic field; plz check first good luck;