Forces

Range of Possible Resultants

Finding the Maximum and Minimum Resultant of Two Forces

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Do Now warm-up prompt

A boy and his sister exert a 5 N force eastward on a dresser. If their mother wants to prevent them from moving the dresser, how large must her force be?

Angles and Resultants

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C. Combining Forces

Range of Possible Resultants

Case III

θ ≠ 0° ≠ 180°

Given

Forces of 100. N and 30. N act on a body.
Find: Largest Possible Resultant.
Find: Smallest Possible Resultant.

↓

Largest Possible Resultant = 100. N + 30. N

= 130 N

Smallest Possible Resultant = 100. N − 30. N

= 70. N

Subtract the two forces to find the Smallest Resultant

Add the two forces to find the Largest Resultant

Concurrent Forces

All forces pass through a common point

Example 1

Concurrent forces diagram, example 1 Resultant construction for example 1

Example 2

Concurrent forces diagram, example 2 Resultant construction for example 2
Concurrent forces, example 3

Not Concurrent

Forces that are not concurrent
Given

Which pair of concurrent forces may have a resultant of 20 nt?
a) 5 nt + 10 nt
b) 20 nt + 20 nt
c) 20 nt + 50 nt
d) 30 nt + 5 nt

Hint: Find the range of possible resultants for each choice

↓
ChoiceMaxMin
a) 5 nt + 10 nt15 nt5 nt
b) 20 nt + 20 nt40 nt0 nt
c) 20 nt + 50 nt70 nt30 nt
d) 30 nt + 5 nt35 nt25 nt

Resultants at Other Angles →