What forces are acting on an object during a bounce?

[Jeff97]

Homework Statement

While I was placing a spanner on the bonnet of a car it slips out of my hand
and falls to the ground.

On this diagram can you show me (draw) vectors showing the
force(s) acting on the spanner at the
instant it hits the ground. Label the forces.

Relevant Equations

N/a

This is not a homework question. I merely am interested in what forces are acting on it.

 

[berkeman]

Even if it's not homework, you can still take a cut at the solution. Start with a free body diagram (FBD) of the wrench and show the force(s) on it just as it makes contact with the ground. Also, are you familiar with the concept of "impulse"?

 

[Jeff97]

@berkeman No, I didn't know " impulse is the integral of a force, F, over the time interval, t, for which it acts. Since force is a vector quantity, impulse is also a vector in the same direction. Impulse applied to an object produces an equivalent vector change in its linear momentum, also in the same direction." Got it now. I drew one. All the forces I got was Weight (mg) downwards and Fn (normal force upwards)

 

[kuruman]

Yes, there are two forces one up and the other down but that is not enough. Where, on the spanner, did you draw them as acting?

 

[Jeff97]

I didn't, really.

 

[berkeman]

I didn't, really.

So on FBDs, it's important to show where the forces are acting, and how that relates to any torques on the object. In this case, the force of hitting the ground (the impulse over the short bounce time) will produce a torque that causes a rotation as part of the bounce. Also, if the wrench was rotating when it hit the ground, that will affect the overall motion.