An object of mass m is initially at rest. after a force of magnitude f acts on it for a time t, the object has a speed v. suppose the mass of the object is doubled, and the magnitude of the force acting on it is quadrupled. in terms of t, how long does it take for the object to accelerate from rest to a speed v now?

It takes to accelerate the object from rest to the speed v.

Explanation:

From Newton's second law:

 (1)

and the definition of acceleration,

(2)

we can solve this problem. Putting (2) in (1) we have:

and solving for and considering the initial time as zero () and the initial velocity also zero () we have:

Now, for a mass and the we can wrtie the same equation:

and substituting and :

So now, it only takes half the time to accelerate the object from rest to the speed v

i think the answer is a and b

i wish you luck

the components of a vector are the parts of the vectors that are to each other.

b perpendicular