QU1:A particle is projected from a point  P(2,0,0)  with a velocity 10m/s making an angle 45 degrees with the horizontal . The plane of projectile motion
through a horizontal  line PQ which  makes an angle of 37 degrees with the +ve X-axis, XY-plane is horizontal .The coordinates of the point where
the particle will strike the line PQ is (taking g=10m/(sec)2):-
(a) (10,6,0)
(b) (8,6,0)
(c) (10,8,0)
(d) (6,10,0)

QU2:Is it possible to have a collision in which all of the K.E. is lost ?
QU3:Explain how linear momentum is conserved when a ball bounces from floor.
QU4:Do you know how to determine whether a force is conservative or not from vector representqtion of a force. For example I give you this question :-
         e.g.A force F=5zi+xyj+x2zk is :-
               a)is conservative
               b)is non-conservative
               c)is conservative along some paths
               d)may be conservative or non conservative depending upon x,y,z
              [NOTE: Here i,j,k stands for i cap,,j cap and k cap respectively and there is an arrow (representing vector) over F.Also, x2 means x to the
               power 2 here.]

answer is b force is non conservative

 

if my answer is correct then the explanation is as follows

 

choose two points A(x1i+y1j+z1k)  and b(x2i+ y2j+ z2k)

 

sum the work done over the two diff paths i.e f.OA + f.AB 

u will find that it is not equal to f.OB

so the force is non conservative

 

also to your first question u require a point through which the line passes

otherwise u cannot solve the qn

 

plz reply indicating if my answer is right or not

How can total K.E. of a system be lost????

This is impossible!!! Here's the reason..

 

According to Law Of Conservation Of Momentum,

Initial momentum = Final momentum

So, m_i x v_i = m_f x v_f

 

=> vf = mi x vi

           ----------

              mf

 

vf can only be zero iff. mf is infinite.

So, net minimum K.E. is 1/2 mf vf(square)

take a case of a plastic collision between a very light moving body and a very heavy stationary one(m2>>>m1)

 

in such cases total kinetci energy of the moving body is transferred to the heavy body and kinetic energy is lost