Physics Review Question

Unit: Magnetism
Year: 1995 Question#: 7
Question: Which combination of concurrent forces could not produce equilibrium?

(1 ) 10.N, 20.N, 50.N
(2 ) 20.N, 30.N, 50.N
(3 ) 30.N, 40.N, 50.N
(4 ) 40.N, 40.N, 50.N

What is this question really asking?

Explanation by: Chad H (partially)

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Answer 1
10.N, 20.N, 50.N

Correct

The least it could be is 10N (20N-10N). The most it could be is 30N (10N+20N). It is not enough to be 50N. Equilibrium is something at a balanced state where forces cancel others out to have it equal zero. With this combination it can not be zero. return to top























Answer 2
20.N, 30.N, 50.N

Incorrect

This combination of vectors could reach equilibrium because any combination of two vectors could create a range where the third vector would fit within the range.
The combination of two vectors could be as large as the sum and as small as the difference. For example, the 20N vector and the 30N vector could produce any vector between 50N (20N + 30N) and 10N (30N - 20N) so the remaining vector, 50N could be cancelled out by the other two.

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Answer 3
30.N, 40.N, 50.N

Incorrect

This combination of vectors could reach equilibrium because any combination of two vectors could create a range where the third vector would fit within the range.
The combination of two vectors could be as large as the sum and as small as the difference. For example, the 30N vector and the 40N vector could produce any vector between 70N (30N + 40N) and 10N (40N - 30N) so the remaining vector, 50N could be cancelled out by the other two. return to top


























Answer 4
40.N, 40.N, 50.N

This combination of vectors could reach equilibrium because any combination of two vectors could create a range where the third vector would fit within the range.
The combination of two vectors could be as large as the sum and as small as the difference. For example, the 40N vector and the 40N vector could produce any vector between 80N (40N + 40N) and 0N (40N - 40N) so the remaining vector, 50N could be cancelled out by the other two. return to top


























What's this question really asking

Of these combinations, what ones could not make the object in a state of balance?


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