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Q.7

Expert-verified
Found in: Page 154

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# In an electricity experiment, a plastic ball is suspended on a -cm-long string and given an electric charge. A charged rod brought near the ball exerts a horizontal electrical force on it, causing the ball to swing out to a angle and remain there. a. What is the magnitude of ? b. What is the tension in the string

(a) Magnitude of electrical force = .

(b) Tension in the string = .

See the step by step solution

## Step 1 : (a) Magnitude :

The greatest extent of size and direction of an item is defined as magnitude.

## Step 2 : (a) Explanation :

Plastic ball mass =, string's length =and the string's angle with the vertical = .

The arrangement's free body diagram is illustrated below.

The force equation in the vertical direction at equilibrium is,

= tension of string,

= plastic ball mass,

= string's angle with the vertical,

= acceleration due to gravity.

The force equation in the horizontal direction at equilibrium is,

= magnitude of electric force.

Substitute for .

Substitute for , for and for to find .

Hence, magnitude is .

## Step 3 : (b) Tension :

The pulling force transferred axially by a string, cable, chain, or similar item, or by each end of a rod, truss member, or similar three-dimensional object is known as tension.

## Step 4 : (b) Explanation :

Plastic ball mass =, string's length =and the string's angle with the vertical = .

Substitute for , for and for in equation to find T.

Hence, string's tension is .