State the time taken for the sledge to move from A to B.
Find the displacement of the sledge from point A up the slope at time $t = 24\,\text{s}$.
Show that the acceleration of the sledge as it moves from B back towards A is $0.50\,\text{m s}^{-2}$.
The combined mass of the child and sledge is $70\,\text{kg}$. The part of their total weight acting down the slope is $80\,\text{N}$. Determine the frictional force on the sledge as it moves from B towards A.
Determine the angle $\theta$ of the slope to the horizontal.
The total mass of the child and sledge is $70\,\text{kg}$. The part of the combined weight of the child and sledge that acts down the slope is $80\,\text{N}$. Determine (i) the frictional force on the sledge as it moves from B towards A, and (ii) the angle $\theta$ of the slope to the horizontal.
Between $t = 4.0\,\text{s}$ and $t = 8.0\,\text{s}$, the child on the sledge sounds a whistle. The whistle produces sound with frequency $900\,\text{Hz}$. The speed of sound in air is $340\,\text{m s}^{-1}$. A man at point A hears the sound. Use Fig. 3.2 to answer the following.
Determine the initial frequency of the sound heard by the man.
Describe and explain qualitatively any change in the frequency of the sound heard by the man.