The line of force of a force F is(-3i cap +j cap +5k cap )N passes through a point (7,3,1).The moment of force Torque =r vector ×f vector about the origin is?

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Solution

The answer is given below :

Given, force (f) = - 3i + j + 5k

and

point (r) = 7i + 3j + k

Now, torque (τ)

= f × r

.....| i j k |
= | -3 1 5 |
.... | 7 3 1 |

= (1 - 15)i - (-3 - 35)j + (-9 -7)k

= -14i + 38j - 16k

So, magnitude of torque

=√((-14^2)+(38^2)+9+(-16^2))

=√1896

=43.54 units(approximately)

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Similar questions

\to F = (\begin{matrix} - 3^i +^j + 5^k \end{matrix}) N

(7, 3, 1)

(\to τ = \to r \times \to F)

\to F = - 3 ˆ i + ˆ j + 5 ˆ k

\to r = 7 ˆ i + 3 ˆ j + ˆ k

^i - 2^j

^i + 2^j

^k

3^k

\to F = (2^i + 3^j + 4^k) N

\to r = (3^i + 2^j +^k) m

F = (2 ˆ i - 3 ˆ j + 4 k)

r = (3 ˆ i + 2 ˆ j + 3 ˆ k)

τ = r \times F

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