Question

A 66-kg man stands on a spring scale in an elevator. Starting from rest, the elevator ascends, attaining its maximum speed of 1.2 m/s in 0.90 s. The elevator travels with this constant speed for 5.0 s, undergoes a uniform negative acceleration for 1.6 s, and then comes to rest. What does the spring scale register in each of the following time intervals?

Answer 1

Answer:735.46N, 626.34N

Explanation: when an elevator ascend, it means it moving against gravity

F= m(a+g)

M=66kg

a=v/t

g=9.81m/s^2

For the first a= 1.2/0.9

a=1.2/0.9

a=1.33m/s2

F=66(1.33+9.81)

F=66(11.143)

F=735.46N

F=m(a+g)

a=v/t

a=-1.6/5

a=-0.32m/s2

F=66(-0.32+9.8)

F=66(9.49)

F=626.34N