Question

6) Un corp de masă m=1kg porneste din repaos din pozitia x = 0 la momentul t = 0 fiind supus actiunii unei forte constante F=1N. Lucrul mecanic efectuat de forta in intervalul de timp 0-1s este:
a) L=0J c) L=0.5J e) L=2J
b) L=1J d) L=0.25J​

Answer 1

The answer is A (A=0J)

We have information about the first position of an object, and we are also informed about the time, and power that acts on the object.

F = 1 N

t1 = 0 s

t2 = 1 s

m = 1 kilo

x0 = 0 m

But we are not informed about the second position of object, so we can hardly say that the object was displaced.

x = 0 m

S = x-x0 = 0 m

If the object isn't displacing, we can't say that it's doing work.

So, A = 0J