Practicing Success
A body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time t is proportional to : |
\(t^{1/2}\) \(t^{3/2}\) \(t^{3/4}\) \(t^2\) |
\(t^{3/2}\) |
\(P = F.v = ma.v\) = \(m \frac{dv}{dt}.v\) \(\frac{P}{m}dt = v.dv\) \(\Rightarrow \int_0^t \frac{P}{m}.dt = \int_0^v v.dv\) \(\Rightarrow \frac{P}{m}.t = \frac{v^2}{2}\) \(\Rightarrow v = [\frac{2P}{m}]^{1/2}.t^{1/2}\) Also, \(s = \int v .dt = \int [\frac{2P}{m}]^{1/2}.t^{1/2}\) \(s = [\frac{2P}{m}]^{1/2}[\frac{2t^{3/2}}{3}]\) \(\Rightarrow s \propto t^{3/2}\) |