Answer:
3a 0.7m/s
3b partially inelastic
4a 8.33 m/s
4b completely inelastic
5. puck: 10.59 m/s octopus: 10.59m/s
6. car: 117.44 m/s truck: 17.44m/s
7a - 1 m/s , the red cart travels to the left
7b) elastic
Explanation:
For all these questions, you have find momentum (P=mv) always remember initial P is always equal to final P
3.
Initial P:
mass of first ball x velocity of first ball + mass of second ball x velocity of second ball
0.5*3.5 + 0.5*0 = 1.75 kg.m/s
final P: also 1.75Kg.m/s
let x be the velocity for first ball
0.5*2.8+0.5*x=1.75
0.5x=1.75-1.4
x=0.35/0.5
x=0.7m/s
b) collision is elastic when KEi = KEf, so calculate and see if that's true
using 1/2mv² we know KEi does not equal to KEf
so the collision is partially inelastic, partially because the ball did not stick together
4.
Initial P:
2575*11 + 825*0 = 28,325 kg.m/s
final P: also 28,325 Kg.m/s
let x be the velocity for both vehicles
(2575+825)x=28325
x=28325/3400
x=8.33 m/s
b) collision is elastic when KEi = KEf, so calculate and see if that's true
using 1/2mv² we know KEi does not equal to KEf
so the collision is completely inelastic, completely because the vechicles slides off together
5
Initial P:
0.115*35 + 0.265*0 = 4.025 kg.m/s
final P: also 4.025Kg.m/s
since they slides off together, the velocity will be the same, so let x be the velocity for the puck and octopus,
(0.115+0.265)x=4.025
x=4.025/0.38
x=10.59
6. Initial P:
565*25+785*12 = 23,545 kg.m/s
final P: also 23,545 Kg.m/s
since they slides off together, the velocity will be the same, so let x be the velocity for the car and truck,
(565+785)x=23545
x=23545/1350
x=17.44
7.
Initial P:
0.25*2 + 0.75*0 = 0.5 kg.m/s
final P: also 0.5 Kg.m/s
let x be the velocity for red cart
0.75*1+0.25*x=0.5
0.25x=0.5-0.75
x=-0.25/0.25
x=-1m/s
b) collision is elastic when KEi = KEf, so calculate and see if that's true
using 1/2mv² we know KEi equals to KEf
so the collision is elastic
