Question

A block of mass = 4.00 kg is supported by a spring scale with unit of measure of Newtons. This spring scale is attached to top of an elevator. The elevator accelerates upward with a = 3.00 m/sec2. What is the reading on the spring scale to 3 significant figures?

Answer 1

Answer:

118 N

Explanation:

Given mass of the block, m = 4.00kg.

The acceleration of the elevator, a = 3.0 m/s^2.

As elevotar attaced with spring scale and accelerating upward

(block and elevator), so total force

$F_N-mg=ma$

Here, mg is the weight of the block downward direction.

or

$F_N=ma+mg=m(g+a)$

substitute the given value, we get

$F_N=4kg(9.8m/s^2+3m/s^2)$

     = 117.6 N = 118 N.

Thus, the reading on the spring scale to 3 significant figures is 118 N.