1)An elevator is moving down with an acceleration of 1.40 m/s^2. A 14.5 kg block hangs from a spring balance fixed to the roof of the elevator. What is the apparent weight of the block?

m*g+m*a
14.5*9.80+14.5*1.40
142.1+20.3
162.4 N

2)A 2.7 kg box is released on a horizontal surface with an initial speed of 2.9 m/s. It moves on the surface with a deceleration of 0.27 m/s^2. Calculate the kinetic friction force on the box.

F=m*a
2.7*0.27
0.729 N

1 answer

i am unsure of #1, but #2 is correct, i beleive. i am also a student and though i am not positive, i have worked the problem several times and am fairly certain this is the correct answer.