Which of the following objects is in equilibrium?

A. an object that moves at constant acceleration
B. an object that moves at constant velocity
C. an object that was thrown straight upward at the moment it had zero velocity
D. an object moving in a circle at constant speed

**Not sure :( Thank you!!

Question

Which of the following objects is in equilibrium?

A. an object that moves at constant acceleration
B. an object that moves at constant velocity
C. an object that was thrown straight upward at the moment it had zero velocity
D. an object moving in a circle at constant speed

**Not sure :( Thank you!!

danjs · Answer

hello

danjs · Answer

Equilibrium means zero net external forces are acting on the object

anonymous · Answer

yes :)

danjs · Answer

An object that is accelerating must have a force by newtons famous second law, F=m*a

danjs · Answer

When an object is thrown straight up in a gravity field, the entire time it is experiencing a force due to gravity

danjs · Answer

Even when it is at rest at the top, there still is gravitational force pulling it down

anonymous · Answer

so based off of that, it would be C? thrown straight upward the moment it has 0 velocity?

danjs · Answer

an object moving in a circle has to have some force moving it in that circle, directed towards the center of the circle

anonymous · Answer

because nothing is acting on it?

danjs · Answer

Otherwise it would move in a straight line

danjs · Answer

No, there is always gravitational force accelerating the ball downwards

anonymous · Answer

ohh okay, so that means C and D are both out? it's between A and B?

because C has gravitational force and the spinning in a circle (D) has some kind of force as well?

danjs · Answer

Now imagine you were moving at a constant velocity, F=m*a   a=0 (constant velocity) so
F = 0

anonymous · Answer

okay:)

danjs · Answer

did you talk about reference frames and inertial observers in class?

anonymous · Answer

ermm i believe so, but i need to refresh on that

danjs · Answer

okay, post up more questions if ya need !

danjs · Answer

Read Richard Feynman's books, you will love physics after that, probably

anonymous · Answer

okay, so wait, for this, the solution is actually D you said? where it spins?

danjs · Answer

No, an object on a curved trajectory has an acceleration towards the center of the circle

danjs · Answer

an acceleration can loosely be defined as , speed up , slow down, or change in direction

anonymous · Answer

and okay, i will see if my library has them:)

ohh so it's the one moving in a straight line? constant velocity? so B?

danjs · Answer

yes, correct B

anonymous · Answer

ah okay, awesome! :) thank you:)

danjs · Answer

yw