HI All 
Firstly, I agree with Wendy,. experimenting with stuff is one of the best ways to learn how and when to use different tools or features, like particles emitting when the object hit’s the wall.
Since this is a Physics simulation,.. to get the object to slide down the wall, after impact, you’ll need to look at what forces are effecting it, (what’s holding it there, and what’s forcing it to drop)
I’d also suggest switching off the default scene gravity, and replacing it with a direction force, pointing down, (to create a “fake gravity”)since the direction force strength can be animated and key-framed which gives you more control than the “Default” scene gravity.
It’s also important to figure out if a physics simulation is the best way to create what you want to happen. (instead of simulating what would happen)
If you want a ball bouncing realistically,.. then it should be easy to simulate that using physics,.
If you want a tomato splatting into a wall, and then “slowly” sliding down it,.... It may be simpler, and easier to control the motion by animating it, instead of trying to accurately simulate it through physics.
Try throwing a few tomatoes against a wall and see how many will burst, but bounce off,.. or drop to the floor,.. instead of sliding slowly down..
It is possible to use some elements of BOTH physics and animation, by simulating the Physics of an object hitting a surface, then converting that motion into key-frames,..which you can then adjust and delete as you need. but you can’t run the physics again, after it’s been converted to key-frames, unless you delete all the key-frames and start again.
You should experiment with key-framing the forces which effect the object,.. (if there are no forces effecting it,. It’ll float in Zero-Gravity )
Hope it helps
j/p
