Physics Help?

Question

PLEASE HELP

NASA has developed Deep-Space 1 (DS-1), a spacecraft that is scheduled to rendezvous with the asteroid named 1992 KD (which orbits the sun millions of miles from the earth). The propulsion system of DS-1 works by ejecting high-speed argon ions out the rear of the engine. The engine slowly increases the velocity of DS-1 by about 19.0 m/s per day.

a) How much time (in days) will it take to increase the velocity of DS-1 by 13400 m/s?

(b) What is the acceleration of DS-1 (in m/s2)?



The left ventricle of the heart accelerates blood from rest to a velocity of +25 cm/s

(c) If the displacement of the blood during the acceleration is +2.0 cm, determine its acceleration (in cm/s2).

(d) How much time does it take for the blood to reach its final velocity?


Starting from rest, a speedboat reaches a speed of 2.2 m/s in 2.2 s.

(e)What is the boat's speed after an additional 2.3 s has elapsed, assuming the boat's acceleration remains the same?

Answer 1

DS -1 question.

v = at + vo --> (v - v0)/a =t = 13400 m/s/19m/s/day

19m/s/day = 19 m/s/(24 hr/day*60min/hr*60sec/min*1 day) = 2.2x10^-4 m/s^2

So t = 13400/2.2x10^-4 seconds = 6.09x10^7 seconds = 705.3 days.

Heart problem:

Use x = (v^2 - v0^2)/(2a) ---> a = (v^2 - v0^2)/(2x)

a = (25^2 - 0)/(2*2) = 156.25 cm/s^2

v = at + v0 ---> t = (v - v0)/a = 25/156.25 =0.16 sec

Boat problem

first find acceleration from v = at + v0 ---> a = v/t = 2.2/2.2 = 1 m/s^2

The speed after additional 2.3 seconds is

v = at+v0 = 1m/s^2*2.3sec + 2.2m/s =4.5 m/s

alternately v = 1 m/s^2*(2.2+2.3 sec) + 0 = 4.5 m/s