Easiest Physics Problem?

2015-11-02 4:02 am
What is the speed of a freely falling baseball 6.6 s after it is dropped from rest?

回答 (5)

2015-11-02 5:46 am
Vfin = g*t = 9.806 m/sec^2*6.6 sec = 64.72 m/sec....directed downward
2015-11-02 5:06 am
Well an object generally accelerates at 9.8 m/s^2. Depends on if the ball was thrown, dropped, forcefully dropped, etc. I would think the ball would take some time to reach 9.8 m/s^2. So we look at intervals. The interval I just thought of was 6.6s. There fore the speed would be 9.8m/s^2 would it not? I'm guessing if you minus inertia. and surface area. This was all thought of in my head as I am learning too so let me know on what you think of my thoughts.
2015-11-02 4:27 am
10 Meters squared per second X 6.6 66ms not counting wind resistance.
2015-11-02 4:12 am
Well lets always start by listing off the things we know/given:
-V0 (the initial velocity) = 0. We know this becuase the problem says its dropped from rest
-g (the acceleration due to gravity) = 9.8 m/s^2 we know this because this is just a given in physics. memorize this if you haven't
-t (time) = 6.6s we know this becuase its given in the problem as well
thats all were given and know. Now what is it asking for? Its asking for a speed at the end of a given time interval. In other words, the Final Velocity which people usually express as Vf. (speed and velocity are basically the same thing, but velocity is speed WITH direction. so 5 mph in the right is NOT the same as 5 mph in the left)

Now which of the Kinematic equations gives us Vf if we know all the other values? Vf = V0 + gt will give us that because we know V0, g, and t. So plugging in the values, we get Vf = 0 + (9.8 * 6.6) which equals 64.68 m/s
參考: I was in ap physics last year
2015-11-07 2:33 am
The acceleration of gravity is 9.80665 m/s/s. Assuming there is no air resistance, an object will increase its speed by 9.80665 m/s each second. The speed at 6.6 seconds is 9.80665 m/s/s *6.6 seconds=64.72 m/s. Taking two significant figures based on your time, the speed is 65 m/s. The value for gravity decreases with distance from the surface of the Earth; that is why it can vary a bit.

http://www.physic-s.net/2015/11/gravity.html


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