Question

According to the work-energy theorem, the amount of work done can be determined using which formula?

W = deltaKE = 2 times m times quantity v Subscript I Baseline Superscript 2 Baseline negative v Subscript f Baseline Superscript 2 Baseline.
W = deltaKE = One half times m times quantity v Subscript I Baseline Superscript 2 Baseline negative v Subscript f Baseline Superscript 2 Baseline.
W = deltaKE = 2 times m times quantity v Subscript f Baseline Superscript 2 Baseline negative v Subscript i Baseline Superscript 2 Baseline.
W = deltaKE = One half times m times quantity v Subscript f Baseline Superscript 2 Baseline negative v Subscript i Baseline Superscript 2 Baseline.

Answer 1

W = ΔKE = (1/2) m (v_f^2 − v_i^2).

Justification: kinetic energy K = (1/2) m v^2, so the change ΔK = K_f − K_i = (1/2) m v_f^2 − (1/2) m v_i^2.