/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 173 A body of mass \(2 \mathrm{~kg}\... [FREE SOLUTION] | 91Ó°ÊÓ

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A body of mass \(2 \mathrm{~kg}\) is moving in a vertical circle of radius \(2 m\). The work done when it moves from the lowest point to the highest point is (a) \(80 \mathrm{~J}\) (b) \(40 \mathrm{~J}\) (c) \(20 \mathrm{~J}\) (d) 0

Short Answer

Expert verified
The work done as the body moves from the lowest point to the highest point is approximately \(80 \,J\), which is most closely approximated by option (a).

Step by step solution

01

Calculate gravitational force

Gravitational force acting on the body can be calculated by using the formula \( F = m \times g \), where m is the mass of the body, g is the acceleration due to gravity \(9.8 \,m/s^2\). Thus, \( F = 2 \,kg \times 9.8 \,m/s^2 = 19.6 \,N\).
02

Determine displacement

The displacement of the body is twice the radius of the circle, as it moves from the lowest point to the highest point. The radius is \(2 \,m\), so the total displacement is \(2 \times 2 \,m = 4 \,m\).
03

Calculate work done

The work done is the product of the force and the displacement. Therefore, work done can be calculated using the following formula: \(W = F \times d\). By inserting the calculated values, the work done is \(19.6 \,N \times 4 \,m = 78.4 \,J\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Gravitational Force Calculation
Understanding the gravitational force acting on an object is crucial in solving problems related to motion, especially in circular paths. The gravitational force can be calculated using the formula:\[ F = m \times g \]where:
  • \( F \) is the gravitational force,
  • \( m \) is the mass of the object, and
  • \( g \) is the acceleration due to gravity, approximately \(9.8 \, m/s^2\) on Earth.
For instance, if you have a mass \( m = 2 \, kg \), you can easily find the gravitational force by multiplying the mass and gravity: \( F = 2 \, kg \times 9.8 \, m/s^2 = 19.6 \, N \). This simple yet essential calculation tells us how much force the Earth exerts on the object. To advance further into solving problems involving vertical circular motion, this force forms the basis of calculating other necessary parameters like work done.
Displacement in Vertical Circle
Displacement in the context of vertical circular motion refers to the straight-line distance between two points in the path of motion. When an object moves from the lowest point of a circle to the highest point, it's crucial to consider the diameter of the circle for calculating displacement. Since the radius is the distance from the center to the perimeter, the total vertical displacement from bottom to top is twice the radius.In this problem, the radius of our vertical circle is given as \(2 \, m\). Hence, the displacement, defined as the direct upwards path from the lowest to the highest point, is \(2 \times 2 \, m = 4 \, m\). The displacement here captures the actual vertical movement, not the path travelled along the curved circle. This displacement is vital for determining the work done by forces in play during this motion, as it provides the necessary direction and magnitude element for our calculations.
Work Done Formula in Physics
In physics, the work done by a force is a measure of energy transfer and is calculated when a force moves an object through a distance. It can be computed using the formula:\[ W = F \times d \]where:
  • \( W \) is the work done,
  • \( F \) is the force in the same direction as displacement, and
  • \( d \) is the displacement the force acts upon.
In the scenario of vertical circular motion, when moving from the lowest point to the highest point, work is done against gravitational force. Using our calculated values:
  • \( F = 19.6 \, N \)
  • \( d = 4 \, m \)
Plugging these into the formula, we get \( W = 19.6 \, N \times 4 \, m = 78.4 \, J \). This result represents the energy expended by the gravitational force over the given displacement in the circle. Understanding how to apply the work done formula helps in analyzing the energy changes in systems involving forces and motion.

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Most popular questions from this chapter

The linear velocity of a point on the equator is nearly (radius of the earth is \(6400 \mathrm{~km}\) ) (a) \(800 \mathrm{~km} / \mathrm{hr}\) (b) \(1600 \mathrm{~km} / \mathrm{hr}\) (c) \(3200 \mathrm{~km} / \mathrm{hr}\) (d) \(6400 \mathrm{~km} / \mathrm{hr}\)

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