Answer:
Check Explanation
Explanation:
According to the work-energy theorem,
workdone between two points = Change in kinetic energy between the two points
And workdone is given mathematically as the dot product of the force and the displacement the force moves through.
W = F.d = /F/ × /d/ cos θ
where /F/ = magnitude of the force
/d/ = magnitude of the displacement
θ = angle between the line of action of the force and the displacement it moves through
a) W = ΔK.E
/F/ × /d/ cos θ = 8.49 J
/F/ = 12 N
/d/ = √[(1²) + (-1)² + (1²)] = √3
12 × √3 × cos θ = 8.49
θ = cos⁻¹ (0.4085)
θ = 65.9°
b) W = ΔK.E
/F/ × /d/ cos θ = -8.49 J
/F/ = 12 N
/d/ = √[(1²) + (-1)² + (1²)] = √3
12 × √3 × cos θ = - 8.49
θ = cos⁻¹ (- 0.4085)
θ = 114.1°
