How hard must a baseball be hit for it to be considered a "grand slam"?

it doesn't matter how hard it is hit

a grand slam is a homerun with the bases loaded

The real answer: A grand slam is a home run that is hit while the bases are loaded.

Because I can't resist the sarcastic answer: A 'grand slam' is when the pitch is thrown at least 90 mph and the resulting hit travels a distance of at least 400 ft. It must be done with a count of at least 2 balls and 1 strike and your team must be either losing by at least 2 runs or winning by at least 3 runs. A grand slam counts for an 'extra' run, but that run doesn't count if your team is in first place when you hit it.

A grandslam is not how hard you homerun when the base's are loaded lol it dosnt matter how hard its hit in baberuth ball (15-16 year olds) i could have a grand slam all i need is base's loaded and a home run the ball could be softly hit over the fence and it would still be a grandslam

It must be hit with no fewer than 1000 psi. Thus the "grand" in grand slam. Now the "shot heard round the world" hit by Bobby Thompson to clinch the pennant for the Giants was called that because it actually traveled around the world and hit the windshield of a chrysler parked at the polo grounds.

a grand slam is a 4 run home run. there must be a player on each base and u have to hit a homer to be considered a grand slam. but i has to be hit hard enough to leav the fence.

a grand slam is simply a home run with the bases loaded, thus earning 4 runs at once. So, I guess the answer to your original question is the same amount as a regular home run.

I can't tell if you're trolling or not, but a grand slam is a homerun hit with runners on all bases. Doesn't matter how hard the ball is hit...

the bases have to be loaded it doesn't matter how hard you hit the ball. the shot heard round the world didn't go around the world they got the name from the revolutionary war. babe Ruth's home run wasn't record breaking the legend says he pointed to center field and the next pitch he hit a home run there

All you need for a grand slam is to have the bases loaded when you hit your home run. That's all.

Pin point accuracy is almost unheard of. I would say the most important thing is to keep the hitters off balance. That is make them worry whether the next pitch is "smoke in their ear" or a "hook low and away." At the highest levels of the game the most important thing is to have more than one pitch you can throw on any count. As a young player I would say that the most important thing is keeping it in the strike zone and in most situations down. If the pitch is going to be elevated let the batter do it. If you don't throw strikes they will wait you out.