Do u need 10 points u have the chance to get it on these qustions?

Question

1. the graph below represents the velocity-time variation of a car's motion.

http://s97.photobucket.com/albums/l218/daanish101/?action=view&current=danishsproject.jpg

2. an alevator is moving down with an acceleration of 1.40 m/s square a 14.5-kg block hangs from a spring balance fixed to the roof of the elevator. what is the appartment weight of the block?

3. given below the position-time graph representing motion of two runners, NIck and lan. use the websites graph to determing which runner has greater average velocity

http://s97.photobucket.com/albums/l218/daanish101/?action=view&current=danishsproject2.jpg

Answer 1

for 1 you use the formula acceleration=Vf-Vi/change in time

a.4.0/5 which is 0.8 m/s^2

b.a=4.4/5 which is o m/s^2

c. a=16-4/10 which is 1.2 m/s^2

also to find the change in time you subtract the seconds like for c to get 10 you had to subtract 20 from 10.

anyways D. a=0-16/10 which is -1.6 m/s^2.

2. W=mg

W=14.5*9.8

W=142.1 N

Fnet=W-T

so W-T=m*a

142.1N-T=1.40*1.45

142.1N=20.3

T=121.8N and that's the answer for that

3. the formula for this is Vaverage=change in x/change in time

so first you find velocity of nick which is v=6/8 and you get 0.75.

Then you find velocity for lan and that's 8/8 which equals 1 and so lan is the fastest runner since his average velocity is greater than nick.