Question

an object with mass of 5kg having velocity of 5km/h.suppose its velocity is changed to 10km/h for 2 hours.find its momentum and also calculate fire applied in order to gets its momentum changed.​

Answer 1

Explanation:

t=10sec

10=5×v[P=mv]

v=2m/s

As F=0.2N

a=

5

0.2

m/s

2

=

25

1

m/s

2

[a=

m

F

]

at t=0,KE=

2

1

×s×(2)

2

[KE=

2

1

mv

2

]

KE

i

=10J

Now, at t=10sec, v

f

=u+at

v

f

=g+

25

1

×10=2.4m/s

2

∴KE

f

=

2

1

×5×(2.4)

2

=14.4J

∴△KE=14.4−10

=4.4J