Question

An upward force of 1:2x104 N acts on an elevator of mass 2:0x103 kg. Calculate the acceleration of the elevator. Take g = 9:8ms-2

Answer 1

Answer on Question #51077 – Physics – Mechanics, Kinematics, Dynamics

Question: an upward force of $1.2 \cdot 10^{4} \, N$ acts on elevator of mass $2.0 \cdot 10^{3} \, kg$. Calculate the acceleration of the elevator. Take $g = 9.8 \, \frac{m}{s^{2}}$.

Solution: let us use the Newton's second law. The object has 2 forces acting on it. Its weight is pushing it down and the elevator is pushing it up. The projection of forces along upward direction is

$$m a = F - m g$$

Here $a$ is acceleration of the lift, $m$ is its mass, $F$ is the upward force. Thus,

$$a = \frac{F}{m} - g = \frac{1.2 \cdot 10^{4}}{2 \cdot 10^{3}} - 9.8 = -3.8 \, \frac{m}{s^{2}}$$

We see that lift is moving downward with acceleration $a = -3.8 \, \frac{m}{s^2}$.

Answer:

lift is accelerating downward at $3.8 \, \frac{m}{s^2}$