
#1
Mar1312, 04:13 PM

P: 201

If I throw something at a 30° angle with a velocity of 10m/s, the vertical component is 5m/s and the horizontal component is 5√3 m/s, which equals 8.66 approximately.
Where did the force to get the body those additional 3.66 m/s come from? I mean, I did only input a force to get the object to 10m/s... 



#2
Mar1312, 04:17 PM

Sci Advisor
P: 5,935

The horizontal and vertical components aren't supposed to be added numerically. Use Pythagorean theorem to get the total, which is the 10 you started with.




#3
Mar1412, 06:30 PM

P: 201

But I clearly have to input more force throwing something twice at (5√2)m/s then throwing that same something once at 10m/s. How can those be equivalent? 



#4
Mar1512, 03:18 PM

Sci Advisor
P: 5,935

Projectile at an angle (sum of vectors)
Doing it in two steps is different. Extreme example  start it horizontally at 100 m/sec, then reverse it with force to make it stop. You will have exerted lots of force, but the projectile will have stopped moving.




#5
Mar1512, 03:30 PM

P: 201

Wouldn't it work if we were concerned with velocity or total distance traveled? 



#6
Mar1612, 03:50 PM

Sci Advisor
P: 5,935

I am not sure what you are asking. However in general terms, any (2 dim.) vector can b resolved into horizontal and vertical components.




#7
Mar2012, 07:19 AM

P: 961

the acceleration to gravity is acting downward. If no gravity involve or gravity in/opposite direction of the velocity then it is useless to resolve it into 2 components. 2. It is a VECTOR addition. Not a scalar addition. In scalar its NOT true 5+5√3 =10 But in Vector it is true, 5+5√3=10, a²+b²=c², 25+75=c² =>c=10 


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