Rituraj Tiwari
Last Activity: 5 Years ago
To determine the scale reading when the elevator is ascending and to find the total tension in the cables, we need to analyze the forces acting on both the elevator and the person standing inside it. Let's break this down step by step.
Understanding Forces in the Elevator
When the elevator ascends, it experiences two main forces: its weight and the tension in the cables. The weight of the elevator is given as 5000 N, and it is moving upward with an acceleration of 3 m/s². The person inside the elevator has a weight of 700 N.
Calculating the Total Forces
Using Newton's second law, we can express the net force acting on the elevator:
Net Force (F_net) = T - W_elevator
Where:
- T = tension in the cables
- W_elevator = weight of the elevator (5000 N)
Since the elevator is accelerating upwards, we can write:
F_net = m * a
Here, m is the mass of the elevator, and a is the acceleration (3 m/s²). First, we need to find the mass of the elevator:
Weight (W) = m * g
Where g is the acceleration due to gravity (approximately 9.81 m/s²). So, we have:
m = W / g = 5000 N / 9.81 m/s² ≈ 509.8 kg
Finding the Tension in the Cables
Now we can substitute the mass into our earlier equation for net force:
F_net = 509.8 kg * 3 m/s² = 1529.4 N
Now, substituting this back into the net force equation:
1529.4 N = T - 5000 N
Solving for T gives:
T = 1529.4 N + 5000 N ≈ 6529.4 N
Scale Reading for the Person Inside the Elevator
The scale reading reflects the apparent weight of the person standing on it. When the elevator is accelerating upwards, the scale will read more than the actual weight of the person due to the additional force from the elevator's acceleration. The apparent weight can be calculated as follows:
Apparent Weight = W_person + m_person * a
To find the mass of the person:
m_person = W_person / g = 700 N / 9.81 m/s² ≈ 71.3 kg
Now, we can calculate the apparent weight:
Apparent Weight = 700 N + (71.3 kg * 3 m/s²) = 700 N + 213.9 N ≈ 913.9 N
Final Results
To summarize:
- The total tension in the cables of the elevator is approximately 6529.4 N.
- The scale reading for the person standing inside the elevator is approximately 913.9 N.
This analysis shows how forces interact in an accelerating system and how they affect measurements like weight on a scale. If you have any further questions or need clarification, feel free to ask!