A body is moving under the action of two forces F1=2 hati-5 hatj;F2=3 hati-4 hatj Its velocity will become uniform under a third force F3 given by

Question

A body is moving under the action of two forces F1=2 hati-5 hatj;F2=3 hati-4 hatj Its velocity will become uniform under a third force F3 given by (A)  5 hati- hatj  (B)  -5 hati- hatj  (C)  5 hati+ hatj  (D)  -5 hati+9 hatj

Tardigrade Admin · Accepted Answer

: For uniform velocity, accleration is zero. Hence resultant force will be zero ∴ F1+F2+F3=0 (2 hati-5 hatj)+(3 hati-4 hatj)+F3=0 Or F3=(-5 hati+9 hatj)

Q. A body is moving under the action of two forces $F_{1} = 2 \hat{i} - 5 \hat{j}; F_{2} = 3 \hat{i} - 4 \hat{j}$ Its velocity will become uniform under a third force $F_{3}$ given by

$5 \hat{i} - \hat{j}$

$- 5 \hat{i} - \hat{j}$

$5 \hat{i} + \hat{j}$

$- 5 \hat{i} + 9 \hat{j}$

: For uniform velocity, accleration is zero. Hence resultant force will be zero $∴$ $F_{1} + F_{2} + F_{3} = 0$ $(2 \hat{i} - 5 \hat{j}) + (3 \hat{i} - 4 \hat{j}) + F_{3} = 0$ Or $F_{3} = (- 5 \hat{i} + 9 \hat{j})$

Q. A body is moving under the action of two forces F1​=2i^−5j^​;F2​=3i^−4j^​ Its velocity will become uniform under a third force F3​ given by

5i^−j^​

−5i^−j^​

5i^+j^​

−5i^+9j^​