JEE Main Physics question
A particle moves with a velocity of (4î−2ĵ+2k̂) m/s under the influence of a constant force F = (10î+3ĵ−2k̂) N. The instantaneous power applied to the particle is W.
Answer: 30
Solution
P = F·v = (10î+3ĵ−2k̂)·(4î−2ĵ+2k̂) = 10×4 + 3×(−2) + (−2)×2 = 40 − 6 − 4 = 30 W.