A 3.00 kg block starts from rest at the top of a $30.0^{\circ}$ incline and accelerates uniformly down the incline, moving 2.00 m in 1.50 s. Find the speed of the block after it has slid a distance of 2.00 m.

A 3.00-kg block starts from rest at the top of a $30.0 ^ { \circ }$ incline and slides 2.00 m down the incline in 1.50 s. Find the speed of the block after it has slid 2.00 m.

If you kick a block so that it starts moving up a rough incline, you observe that the acceleration of the block while moving up the incline is different from the acceleration when the block is sliding back down the incline. (a) Draw a force diagram for the block when it is moving up the incline and down the incline. (b) Explain why the accelerations are different and compare their magnitudes.

A $1.25-\mathrm{kg}$ block is pulled at constant speed up a frictionless $15^{\circ}$ incline with constant force $\vec{F}$ directed up the incline. Identify all forces acting on the block, and use Newton's first law to find $\vec{F}$. Find the work done by $\vec{F}$ in moving the block $0.60 \mathrm{~m}$ up the incline. Find the work done by gravity over the same path. (d) Combine your results to find the net work done on the block.

A 45 kg block of ice slides down a frictionless incline 1.5 m long and 0.91 m high. A worker pushes up against the ice, parallel to the incline, so that the block slides down at constant speed. (a) Find the magnitude of the worker’s force. How much work is done on the block by (b) the worker’s force, (c) the gravitational force on the block, (d) the normal force on the block from the surface of the incline, and (e) the net force on the block?

A 3.00 kg block starts from rest at the top of a $30.0^{\circ}$ incline and accelerates uniformly down the incline, moving 2.00 m in 1.50 s. Find the coefficient of kinetic friction between the block and the incline.

A 3.00-kg block starts from rest at the top of a $30.0 ^ { \circ }$ incline and slides 2.00 m down the incline in 1.50 s. Find the coefficient of kinetic friction between the block and the incline.

A 3.00-kg block starts from rest at the top of a 30 degrees incline and slides a distance of $2.00 \mathrm{~m}$ down the incline in $1.50 \mathrm{~s}$. Find the coefficient of kinetic friction between block and plane.

A device called a railgun uses the magnetic force on currents to launch projectiles at very high speeds. An idealized model of a railgun is illustrated as we discussed earlier. A $1.2 \mathrm{~V}$ power supply is connected to two conducting rails. A segment of copper wire, in a region of the uniform magnetic field, slides freely on the rails. The wire has a $0.85 \mathrm{~m} \Omega$ resistance and a mass of $5.0 \mathrm{~g}$. Ignore the resistance of the rails. When the power supply is switched on,
a. What is the current?
b. What are the magnitude and direction of the force on the wire?
c. What will be the wire's speed after it has slid a distance of $1.0 \mathrm{~mm} ?$

Two ice skaters, one with a mass of $57 \mathrm{~kg}$ and the other with a mass of $75 \mathrm{~kg}$, stand facing each other on the surface of a frozen pond. One of the skaters exerts a $135 \mathrm{~N}$ force against the other. Calculate the magnitude of the acceleration of each skater.

Two ice skaters are holding hands at the center of a frozen pond when an argument ensues. Skater A shoves skater $\mathrm{B}$ along a horizontal direction. Identify (a) the horizontal forces acting on $\mathrm{A}$

Two ice skaters are holding hands at the center of a frozen pond when an argument ensues. Skater A shoves skater $\mathrm{B}$ along a horizontal direction. Identify (b) those acting on $\mathrm{B}$.

A roller coaster car has a mass of $400 \mathrm{~kg}$ and a speed of $15 \mathrm{~m} / \mathrm{s}$.

a) What is the $K E$ of the roller-coaster cart?

b) What will be the GPE of this roller-coaster cart at its highest point, where $K E=0$ at that point?

c) How high can the roller-coaster cart go with this much energy?

A 3.00 kg block starts from rest at the top of a $30.0^{\circ}$ incline and accelerates uniformly down the incline, moving 2.00 m in 1.50 s. Find the magnitude of the frictional force acting on the block.