Practicing Success
A boy drags a toy box 2.0 m along the floor by means of a force of 10 N directed downward at an angle of 60° to the horizontal to dissipate power of 6.7 W. For how long is the boy pushing the toy ? |
5 s 3 s 1.5 s None of these |
1.5 s |
\(\text{Work done } = \text{Force x Displacement x } \cos {\theta}\) \(W = 10 \text{ N x } 2.0 \text{ m x } \cos {60^o} = 10 \text{ J}\) \(\text{Power = } \frac{\text{Work Done}}{\text{Time}}\) \(6.7 \text{ W} = \frac{10 \text{ J}}{t}\) \(\Rightarrow t = 1.49 \text{ s} ≈ 1.5\text{ s} \) |