Question

Mamentum, BK Ey d) Nothing Apear falls off a tree. Ignoring Jair resistance, which guantities are a conserved chering the fall ? arde 14 the correct answars. More than - one answer may be correct. Mechanical energy; 2 pieces of donc lide del and chick together. During the 1 collision, whith guantities and conserved arce the correct answer a) Momentum ; b) KE; Mechanical energy d) Nothing 10 2 steel balls collide o lastically. During the collision which quantities are conserval! a) Momentum ; 6) KE L (c) Mechanical energy; d) Nothing IM I thing a ball straight up in the an. While is it in the air, and ignoring an. resistance, which quantities a) GLE; b)KE ;) Mechanical (d) Mothing energy 6 I throw a ball up in the air at an angle of 30 while it is in the dir and ignoing Jau resistance, which quantities fare conserved? a) OLE; b)KE) Mechanical 22 d) Nothing energy TO A block slides horizatally on a rough surface. What ist the net work on the block! a) Positive; b) Negative) c) Zero ; dh can't fell fare conserved!

Answer 1

I(A). O- O pea initial velocity is zero. (a) Momentum will not conserve. Because velocity will increase as bear goes down. 6) Mechanical Energy will conserve. Because gravitation force is conservative force. all the potential Energy will convert into kinetic therg y at ground. (b)- KE at top is zero. velocity will increase as bear goes downward". o increases K-E-also increases. K.EE mu (d) Notting therefore c option is correct. w

1(B) Õ oo (a) Momentum - will conseroed because there is no force along horizontal direction dt 10- of dp=0 iP= const ] (b) KE Energ will not conserve because collision is perfectly inelastic that is some part of initial Kinetic energy will convert into heat. © Mechanical thergys K-E 4PLE ( Jame Reason as above mentioned). ② Nothing option is correct.

10 In Elastic collision momentum and Kinetic energy are conserve quantity Because there is no suff2055 as a form of heat. therefore option a, b and c are correct option: 2 (4) v=o o 30 t=t tzt st- - U=D Mechanical Energy at ground = {map+ mgloss moz-OS Mechanical thergy at top- I m coll+ngh & How I am finding height h.

UT = us-agh O= 0%-agh ata agha ha putting on in equ ® ha = mgh Mechanical = Žmo Energy at toß Mechanical Energy at bottom = Mechanical Energy at top. we com also see at any point Mechanical energy is conserve while Kinectic energy momentum and potential Energy not conserve therefore option G is correct. KE-mop P. E-mgh

throughout the Motion velocity and lièight change therefore KE and P.E is not conserve quantity. But Mechanical energy conserved as I earlier described NOTE - Motion under gravitational force having Mechanical Energy conserved if there is no Resisting or friction force. option c is correct. 20 block the have work Energy theorem WINET = Dk.E = K.Et - kein - 2 muffmann e Vin because res, friction force will Meduce velocity of block

| PINET= 6-)) option is correct.