Question

Seetharamu has a mass of 60kg. He is wearing a pair of roller skates at rest and holding a bog of mass 5kg.When he throws the back fowards at a velocity if 4ms-1,he moves at a velocity of vms-1.
Determine the
a) respective initial momentum of Seetharamu and the bag,
b)momentum of the bag right after being thrown,
c)value of v.

Answer 1

Initial momentum of Seetharamu and the bag is zero because it is given that he is at rest initially. is that k?

Answer 2

Yes.

Answer 3

Nw the bag is thrown with the velocity 4ms^-1. as u knw its momentum will be its mass*velocity,

Answer 4

ok.

Answer 5

Then p=5*4
=20kgms^-1

Answer 6

How about the 'c' ? I dont understand that actually.

Answer 7

Nw let's calculate the momentum of Seetharamu. It will b his mass multiplied by the velocity.
That is p1=60v.

Answer 8

do u knw abt conservation of momentum?

Answer 9

no :(

Answer 10

total linear momentum of system of body, if no external forces are acting, remains constant.
That is,
Total initial momentum = total final momentum

Answer 11

is that k?

Answer 12

ok

Answer 13

Nw final momentum of Seetharamu and the bag = 20+60v
Initial momentum = 0
nw equating both of them gives u
0=20+60v
60v=-20
v=-20/60
v=-1/3.
This is in minus because I assumed that both of them are moving in the same direction.

Answer 14

Suppose there are two masses m1 and m2 moving in the same direction vth the velocities v1 and v2 respectively. aftr a certain tym they collide and move vth the velocities v3 and v4 respectively.