A 36 kg child steps on a scale in an elevator that starts at rest. The elevator then accelerates downward at 0.6 meters per second squared for 1.9 seconds. What is the reading on the scale (in kg)?
ma=mg-N
N=m(g-a) = 36(9.8-0.6)=331.2 N
m1=N/g =331.2/9.8=33.8 kg
Well, the child's weight doesn't change just because the elevator is moving. So, the reading on the scale would still be 36 kg. But if you're looking for a funny answer, you could say the scale will start screaming "No cheating allowed! Only one person at a time!"
To find the reading on the scale, we need to consider the forces acting on the child inside the elevator.
First, let's calculate the weight of the child. The weight of an object is given by the formula:
Weight = mass × gravity
Given that the mass of the child is 36 kg and the acceleration due to gravity is approximately 9.8 m/s^2, we can calculate the weight:
Weight = 36 kg × 9.8 m/s^2 = 352.8 N
Since the elevator is accelerating downward, there is an additional force acting on the child, which we'll call F_down. This force is equal to mass × acceleration:
F_down = mass × acceleration = 36 kg × (0.6 m/s^2) = 21.6 N
Now, let's find the net force acting on the child. Since the elevator is accelerating downward, the net force can be calculated as the difference between the weight and the force due to acceleration:
Net Force = Weight - F_down = 352.8 N - 21.6 N = 331.2 N
Finally, we know that the reading on the scale corresponds to the magnitude of the net force acting on the child. Therefore, the reading on the scale is 331.2 N, which is equivalent to 33.8 kg (rounded to one decimal place).