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M2 anyone?

Manasa

Manasa

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anyone help out on how to do qs where were supposed to only consider energy changes and solve smth? like my prob is when it says that... idk which energy = which energy and usually these parts i get it wrong...help out?
 
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saifulahmed49

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Manasa said:
anyone help out on how to do qs where were supposed to only consider energy changes and solve smth? like my prob is when it says that... idk which energy = which energy and usually these parts i get it wrong...help out?
Click to expand...
depends. For example-
1.u released a ball from height h and there is no air friction. as the ball falls it loses G.P.E and gains K.E. so just before impact with floor we assume all the G.P.E. is converted into its K.E.
2. this time there is air friction. work done against friction (lets say W.D.F.)= frictional force x distance travelled. so as the ball falls all the G.P.E. is converted into K.E. and some are used as W.D.F......(K.E.+W.D.F.) gained = G.P.E. lost
3. if you throw a ball from ground, it has K.E....as it goes up it gains G.P.E. and loses K.E.
4. if there is air friction it gains W.D.F and G.P.E and loses K.E....so when does the ball reaches maximum height?when G.P.E.+W.D.F= (K.E. at start)...
the thing is that to do a work against something energy from somewhere else is converted. and the total energy of a system remains constant. suppose u throw a ball with speed v and it gains K.E. This K.E. may be converted into other energies, but if you add all those other energies it should be same to the starting energy.
I'm not good in explaining stuffs, hope you get it. :)
 
Hasan Naqvi

Hasan Naqvi

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saifulahmed49 said:
depends. For example-
1.u released a ball from height h and there is no air friction. as the ball falls it loses G.P.E and gains K.E. so just before impact with floor we assume all the G.P.E. is converted into its K.E.
2. this time there is air friction. work done against friction (lets say W.D.F.)= frictional force x distance travelled. so as the ball falls all the G.P.E. is converted into K.E. and some are used as W.D.F......(K.E.+W.D.F.) gained = G.P.E. lost
3. if you throw a ball from ground, it has K.E....as it goes up it gains G.P.E. and loses K.E.
4. if there is air friction it gains W.D.F and G.P.E and loses K.E....so when does the ball reaches maximum height?when G.P.E.+W.D.F= (K.E. at start)...
the thing is that to do a work against something energy from somewhere else is converted. and the total energy of a system remains constant. suppose u throw a ball with speed v and it gains K.E. This K.E. may be converted into other energies, but if you add all those other energies it should be same to the starting energy.
I'm not good in explaining stuffs, hope you get it. :)
Click to expand...

how about when taking vertical displacement in projectile motion? when is it positive and when is it negative? in the equation y = usint - 0.5gt^2
 
Manasa

Manasa

Messages
276
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402
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73
saifulahmed49 said:
depends. For example-
1.u released a ball from height h and there is no air friction. as the ball falls it loses G.P.E and gains K.E. so just before impact with floor we assume all the G.P.E. is converted into its K.E.
2. this time there is air friction. work done against friction (lets say W.D.F.)= frictional force x distance travelled. so as the ball falls all the G.P.E. is converted into K.E. and some are used as W.D.F......(K.E.+W.D.F.) gained = G.P.E. lost
3. if you throw a ball from ground, it has K.E....as it goes up it gains G.P.E. and loses K.E.
4. if there is air friction it gains W.D.F and G.P.E and loses K.E....so when does the ball reaches maximum height?when G.P.E.+W.D.F= (K.E. at start)...
the thing is that to do a work against something energy from somewhere else is converted. and the total energy of a system remains constant. suppose u throw a ball with speed v and it gains K.E. This K.E. may be converted into other energies, but if you add all those other energies it should be same to the starting energy.
I'm not good in explaining stuffs, hope you get it. :)
Click to expand...
tyysmmmm!!! i got it noww :)
 
Manasa

Manasa

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Hasan Naqvi said:
how about when taking vertical displacement in projectile motion? when is it positive and when is it negative? in the equation y = usint - 0.5gt^2
Click to expand...
y is negative.... if u take upward to b positive then g is - and vice versa is true..
 
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saifulahmed49

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it was okay, only in the easiest projectile ever i wrote 14^2(sin^2x+cos^2 x) as 2*14^2.... :'(
by the way in impulse was theta=2??
 
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