Question

A spacecraft's landing is cushioned by air bags. As it lands on Mars, the velocity of downward fall is 20 meters/second. Immediately after impact the velocity is 10 meters/second. If the spacecraft has a mass of 7.1 × 10Ê kilograms, what is the value of the impulse?

Hmmm?

Answer 1

the impulse is the change in momentum

Answer 2

wait... after impact, what is the direction of the velocity?

Answer 3

it cant be travelling downwards still lol

Answer 4

It doesnt say lol. Thats my entire question?

Answer 5

hmm lets assume the direction of velocity is now upwards. will you be able to calculate the impulse?

Answer 6

Yes?

Answer 7

Impulse = change in momentum
The "change in momentum" means the final momentum minus the initial momentum?

Answer 8

yes correct.

Answer 9

So would that be, Impulse=10m/s - 20m/s or am i mistaking?

Answer 10

i got confused ._.

Answer 11

momentum is mass x velocity

Answer 12

so final momentum is -10 x mass, initial momentum is 20 x mass . then take final - initial to find the change in momentum

Answer 13

-10 because the velocity after impact is traveling in the opposite direction

Answer 14

So it will be [-10 x (7.1 × 10^4)] - [20 x (7.1 × 10^4)]

Answer 15

Blah! Now let me see if i can work it out :)

Answer 16

By any chance would it be 21.3 x10^4 ?

Answer 17

yes that is what i got =)

Answer 18

Yess! You are great help honestly! :)

Answer 19

But my choices are these:

A. 1.2 x 10^4
B. 2.2 x 10^5
C. 7.1 x 10^5
D. 3.6 x 10^4

Answer 20

Would it be B?

Answer 21

then it is C

Answer 22

remove the negative from the -10 x mass

Answer 23

that means to say that the velocity after impact is still in the same direction as when the spaceship is falling O.O

Answer 24

i think it's because of the airbags! my bad =(

Answer 25

Oh okay lol we knew that :) And dont worry its alright :)