Question

Question on Impulse. so i already calculated the answer.

A box (0.015 kg) is sliding along the table at 5.0m/s. I try to stop it but only slowed to 1.6m/s. Determine the impulse of the box.

so the answer was -0.015 kgm/s

so my notes said that the negative sign identifies that the impulse was acting in a negative direction, could you guys explain that?

Answer 1

In a coordinate system, you were moving in a positive direction (let this be along x), the impulse opposed the direction of movement, so it's negative.

Answer 2

you could've picked movement in the negative direction (so your velocity was negative), the impulse opposing the motion would have then been positive.

Answer 3

when you say you pick the movement your talking about the force your applying right?

Answer 4

so in the question i posted i was applying force in the positive direction ?

Answer 5

Movement as in the velocity the object has initially whilst sliding. I'm not sure that there a net force being applied to the object to make it slide (it's not mentioned in the question), but there was a force applied in the direction opposing the initial movement (sliding) to cause the change in momentum.

Answer 6

but yes, the force you apply to try to stop the box is negative in terms of the coordinates