Paul Morris Solutions for Chapter: Free to Move?, Exercise 8: SOME SUMMATIVE PROBLEMS TO TRY

If the cars in the below figure all have an engine thrust of $1000 \mathrm{N}$, a state which one will have the greatest acceleration. Justify your answer with reference to Newton's laws.

A rifle bullet is fired with a velocity of $240 \mathrm{m} {\mathrm{s}}^{-1}$ and a mass of $100 \mathrm{g}$. A van has a velocity of $1 \mathrm{m} {\mathrm{s}}^{-1}$ and a mass of $2.4 \mathrm{tonnes}$. Compare the momentum of both.

A rifle bullet is fired with a velocity of $240 \mathrm{m} {\mathrm{s}}^{-1}$and a mass of $100 \mathrm{g}$.  State the size of the momentum of the rifle after the bullet is fired.

A rifle bullet is fired with a velocity of $240 \mathrm{m} {\mathrm{s}}^{-1}$and a mass of $100 \mathrm{g}$.  The bullet hits a target and is stopped in $10 \mathrm{ms}$. Outline the forces acting when this occurs and calculate their size and direction.

A van has a velocity of $1 \mathrm{m} {\mathrm{s}}^{-1}$and a mass of  $2.4 \mathrm{tonnes}$. The van accelerates from $1 \mathrm{m} {\mathrm{s}}^{-1}$ to $5 \mathrm{m} {\mathrm{s}}^{-1}$in $10 \mathrm{s}$. Calculate the extra force produced by the engine during this time.

A van has a velocity of $1 \mathrm{m} {\mathrm{s}}^{-1}$and a mass of  $2.4 \mathrm{tonnes}$. The van accelerates from $1 \mathrm{m} {\mathrm{s}}^{-1}$ to $5 \mathrm{m} {\mathrm{s}}^{-1}$in $10 \mathrm{s}$. A strong wind starts to blow and the van's speed drops by $10\%$ in $10 \mathrm{s}$. Calculate the additional drag produced by the wind.

A van has a velocity of $1 \mathrm{m} {\mathrm{s}}^{-1}$and a mass of  $2.4 \mathrm{tonnes}$. The van accelerates from $1 \mathrm{m} {\mathrm{s}}^{-1}$ to $5 \mathrm{m} {\mathrm{s}}^{-1}$in $10 \mathrm{s}$. The van turns around a corner, still at a constant speed  of $5 \mathrm{m} {\mathrm{s}}^{-1}$. Your teacher tells you that the van is accelerating. State whether you agree or not. Explain your reasons.

A submarine has a mass of $5 \mathrm{tonnes}$. State the buoyancy required for it to float stationary in the water.