Question

Zach, whose mass is 85 kg, is in an elevator descending at 8 m/s. The elevator takes 3.2 s to brake to a stop at the first floor.What is Zach's weight while the elevator is braking?

Answer 1

Zach's weight while the elevator is braking is 1513 N.

Step-by-step explanation:

Zach's weight while the elevator is braking can be determined by calculating the force exerted on him. Since the elevator is descending and braking, the acceleration is in the opposite direction to the gravitational force. So the net force acting on Zach is the difference between the gravitational force and the force due to acceleration.

To calculate the force due to acceleration, we can use Newton's second law: F = ma. The force due to acceleration is given by the mass of Zach times the acceleration of the elevator. In this case, the mass is 85 kg and the acceleration is the negative value of 8 m/s^2. So the force due to acceleration is -680 N.

Therefore, the weight of Zach while the elevator is braking is the difference between his actual weight and the force due to acceleration. His actual weight is given by W = mg, where m is the mass and g is the acceleration due to gravity. Assuming g = 9.8 m/s^2, his weight is 833 N. So his weight while the elevator is braking is 833 N - (-680 N) = 1513 N.

Answer 2

Step-by-step explanation:

acceleration = 8/3.2 = 2.5m/s² ( acceleration due to gravity = g ).

mass = 85 kg.

weight = mg = 85×2.5 = 212.5N .

hope this helps you.