Question

感激不尽一个物体受竖直向上F的作用,当拉力F1=140N时,物体向上的加速度为4m/每二次方秒.不计空气阻力,取g=10

Answer 1

(1)m=F合/a

=(140-G)/4m/s^2

=140/4m/s^2-(m*10m/s^2)/4m/s^2

m=35-2.5m

3.5m=35

m=10kg

(2)

s=1/2at^2

=1/2*4m/s^2*2s

=4m

vt=at

=4m/s^2*2s

=8m/s

(3)

s'=4s=16m

所以a'=4a=16m/s^2

F合'=m*a'

=10kg*16m/s^2

=160N

F拉=F合'+G

=160N+100N

=260N