Question

In a two-body collision in a closed, isolated system,
a)momentum is always conserved.
b)kinetic energy is always conserved.
c)neither momentum nor kinetic energy is conserved.
d)both momentum and kinetic energy are always conserved

Determine the momentum of a 2250 kg pickup truck moving with a velocity of 25 m/s to the east.
1410000 kgm/s
90 kgm/s
5600 kgm/s
56000 kgm/s

Answer 1

for the first parst a) is correct, since in any closed and isolated system momentum is always conserved.

for the second part, momentum=mass x velocity so you have
2250 x 25 = 56250 kg*m/s which rounds to 56000 kg*m/s with sig figs

Answer 2

for the first part b) is incorrect since KE is only conserved in elastic collisions.