Find the kinetic energy of a \(2.0\,\mathrm{kg}\) object moving at \(3.0\,\mathrm{m\,s^{-1}}\).

A \(1.5\,\mathrm{kg}\) object speeds up from \(4.0\,\mathrm{m\,s^{-1}}\) to \(7.0\,\mathrm{m\,s^{-1}}\). Find the net work done on it.

A \(2.0\,\mathrm{kg}\) object starts from rest. Net work \(40\,\mathrm{J}\) is done on it. Find its final speed.

If an object's speed is doubled, by what factor does its kinetic energy change?

A \(3.0\,\mathrm{kg}\) cart moving at \(2.0\,\mathrm{m\,s^{-1}}\) has \(48\,\mathrm{J}\) of net work done on it. Find its final speed.

A brake does \(-250\,\mathrm{J}\) of work on a \(5.0\,\mathrm{kg}\) object and brings it to rest. Find the object's initial speed.

A \(4.0\,\mathrm{kg}\) object moving at \(6.0\,\mathrm{m\,s^{-1}}\) has \(30\,\mathrm{J}\) of negative net work done on it. Find its final speed.

A \(10\,\mathrm{N}\) net force acts over \(6.0\,\mathrm{m}\) on a \(4.0\,\mathrm{kg}\) object initially moving at \(2.0\,\mathrm{m\,s^{-1}}\). Find the final speed.

A \(0.50\,\mathrm{kg}\) ball moving at \(12\,\mathrm{m\,s^{-1}}\) hits a soft barrier and stops. How much work does the barrier do on the ball?

Explain why the work-energy principle gives final speed but not the final direction of motion.

A \(4.0\,\mathrm{kg}\) crate initially moves at \(1.0\,\mathrm{m\,s^{-1}}\). A \(25\,\mathrm{N}\) force pulls at \(30^\circ\) above horizontal for \(6.0\,\mathrm{m}\), while friction does \(-48\,\mathrm{J}\) of work. Find the final speed and change in kinetic energy.

A \(900\,\mathrm{kg}\) car at \(20\,\mathrm{m\,s^{-1}}\) is stopped by a constant braking force of \(4500\,\mathrm{N}\). Find the stopping distance.

A \(0.20\,\mathrm{kg}\) puck starts at \(5.0\,\mathrm{m\,s^{-1}}\). It crosses a rough patch \(1.5\,\mathrm{m}\) long where friction has magnitude \(0.60\,\mathrm{N}\), then immediately enters a smooth region where a constant forward force of \(0.40\,\mathrm N\) acts for \(2.0\,\mathrm m\). Find the speed at the end of the smooth region.

A \(6.0\,\mathrm{kg}\) object is moving at \(4.0\,\mathrm{m\,s^{-1}}\). How much positive net work is needed to triple its speed, and what fraction of the final kinetic energy is this added work?

A \(5.0\,\mathrm{kg}\) sled starts from rest and slides \(8.0\,\mathrm{m}\) down a \(25^\circ\) incline. The coefficient of kinetic friction is \(0.15\). In the final \(2.0\,\mathrm m\), an additional constant resistive force of \(18\,\mathrm N\) acts up the slope. Use work-energy to find the speed at the bottom.

A \(2.0\,\mathrm{kg}\) block starts at \(3.0\,\mathrm{m\,s^{-1}}\) on a horizontal surface. A forward \(18\,\mathrm{N}\) force acts for \(2.0\,\mathrm{m}\), then a backward \(12\,\mathrm{N}\) force acts for \(3.0\,\mathrm{m}\). Determine whether the block stops during stage 2; if not, find final speed.