Question

You are standing on a bathroom scale in an elevator in a tall building. Your mass is 64 kg. The elevator starts from rest and travels upward with a speed that varies with time according to v(t) = (3.0 m/s2)t + (0.20 m/s3)t2. When t = 4.0 s, what is the reading on the bathroom scale?

Answer 1

= 922N

Step-by-step explanation:

m = 64kg

v(t) = (3.0 m/s²)t + (0.20 m/s³)t².

t = 4.0s

differentiation of v(t) so the acceleration is given by

`a(t) = ( dv(t))/(dt) \\ = 3.0 + 0.4t\\ t = 4s\\a(4) = 3.0 + 0.4(4)\\= 4.6ms^-^2`

using Newton’s second law

F (net) = ΣFg = ma

⇒R - w = ma

R = m(a + g)

= 64 (9.81 + 4.6)

= 922N