A force (4 hati+ hatj-2 hatk)N acting on a body maintains its velocity at (2 hati+2 hatj+3 hatk)ms-1 . The power exerted is

Question

A force (4 hati+ hatj-2 hatk)N acting on a body maintains its velocity at (2 hati+2 hatj+3 hatk)ms-1 . The power exerted is (A) 4W (B) 5W (C) 2W (D) 8W

Tardigrade Admin · Accepted Answer

Force, vecF = (4 hati + hatj-2 hatk) N Velocity, vecv = (2 hati + 2 hatj+3 hatk) ms-1 Power, p = vecF ⋅ vecv = (4 hati + hatj-2 hatk)⋅(2 hati + 2 hatj+3 hatk) = (8 + 2 - 6 )W = 4 W

Q. A force $(4 \hat{i} + \hat{j} - 2 \hat{k}) N$ acting on a body maintains its velocity at $(2 \hat{i} + 2 \hat{j} + 3 \hat{k}) m s^{- 1}$ . The power exerted is

4W

5W

2W

8W

1W

Force, $F = (4 \hat{i} + \hat{j} - 2 \hat{k}) N$
Velocity, $v = (2 \hat{i} + 2 \hat{j} + 3 \hat{k}) m s^{- 1}$
Power, $p = F \cdot v = (4 \hat{i} + \hat{j} - 2 \hat{k}) \cdot (2 \hat{i} + 2 \hat{j} + 3 \hat{k})$
$= (8 + 2 - 6) W = 4 W$

Q. A force (4i^+j^​−2k^)N acting on a body maintains its velocity at (2i^+2j^​+3k^)ms−1 . The power exerted is

4W

5W

2W

8W

1W

Force, F=(4i^+j^​−2k^)N Velocity, v=(2i^+2j^​+3k^)ms−1 Power, p=F⋅v=(4i^+j^​−2k^)⋅(2i^+2j^​+3k^) =(8+2−6)W=4W

Q. A force $(4 \hat{i} + \hat{j} - 2 \hat{k}) N$ acting on a body maintains its velocity at $(2 \hat{i} + 2 \hat{j} + 3 \hat{k}) m s^{- 1}$ . The power exerted is

Force, $F = (4 \hat{i} + \hat{j} - 2 \hat{k}) N$
Velocity, $v = (2 \hat{i} + 2 \hat{j} + 3 \hat{k}) m s^{- 1}$
Power, $p = F \cdot v = (4 \hat{i} + \hat{j} - 2 \hat{k}) \cdot (2 \hat{i} + 2 \hat{j} + 3 \hat{k})$
$= (8 + 2 - 6) W = 4 W$