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?
Question
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