A small blimp is used for advertising purposes at a football game. It has a mass of $93.5 \mathrm{~kg}$ and is attached by a towrope to a truck on the ground. The towrope makes an angle of $53.3^{\circ}$ downward from the horizontal, and the blimp hovers at a constant height of $19.5 \mathrm{~m}$ above the ground. The truck moves on a straight line for $840.5 \mathrm{~m}$ on the level surface of the stadium parking lot at a constant velocity of $8.90 \mathrm{~m} / \mathrm{s}$. If the drag coefficient $(K$ in $F=K v^2$ ) is $0.500 \mathrm{~kg} / \mathrm{m}$, how much work is done by the truck in pulling the blimp (assuming there is no wind)?

A force given by $\vec{F}(x)=5 x^3 \hat{x}$ (in $\mathrm{N} / \mathrm{m}^3$ ) acts on a 1.00-kg mass moving on a frictionless surface. The mass moves from $x=2.00 \mathrm{~m}$ to $x=6.00 \mathrm{~m}$. b) If the mass has a speed of $2.00 \mathrm{~m} / \mathrm{s}$ at $x=2.00 \mathrm{~m}$, what is its speed at $x=6.00 \mathrm{~m} ?$

A ski jumper glides down a $30.0^{\circ}$ slope for $80.0 \mathrm{ft}$ before taking off from a negligibly short horizontal ramp. If the jumper's takeoff speed is $45.0 \mathrm{ft} / \mathrm{s}$, what is the coefficient of kinetic friction between skis and slope? Would the value of the coefficient of friction be different if expressed in SI units? If yes, by how much would it differ?

A horse draws a sled horizontally across a snow-covered field. The coefficient of friction between the sled and the snow is $0.195$, and the mass of the sled, including the load, is $202.3 \mathrm{~kg}$. If the horse moves the sled at a constant speed of $1.785 \mathrm{~m} / \mathrm{s}$, what is the power needed to accomplish this?

An ideal spring has the spring constant $k=440 \mathrm{~N} / \mathrm{m}$. Calculate the distance this spring must be stretched from its equilibrium position for $25 \mathrm{~J}$ of work to be done.

You push your couch a distance of 4.00 m across the living room floor with a horizontal force of 200.0 N. The force of friction is 150.0 N. What is the work done by you, by the friction force, by gravity, and by the net force?

A force given by $\vec{F}(x)=5 x^3 \hat{x}$ (in $\mathrm{N} / \mathrm{m}^3$ ) acts on a 1.00-kg mass moving on a frictionless surface. The mass moves from $x=2.00 \mathrm{~m}$ to $x=6.00 \mathrm{~m}$. a) How much work is done by the force?

A soccer ball is kicked from the ground with an initial speed of 12 m/s at an angle of $32^{\circ}$ above the horizontal. What are the x and y positions of the ball 0.50 s after it is kicked?

A spring with $k=10.0 \mathrm{~N} / \mathrm{cm}$ is initially stretched $1.00 \mathrm{~cm}$ from its equilibrium length. a) How much more energy is needed to further stretch the spring to $5.00 \mathrm{~cm}$ beyond its equilibrium length? b) From this new position, how much energy is needed to compress the spring to $5.00 \mathrm{~cm}$ shorter than its equilibrium position?

A man throws a rock of mass $m=0.325 \mathrm{~kg}$ straight up into the air. In this process, his arm does a total amount of work $W_{\text {net }}=115 \mathrm{~J}$ on the rock. Calculate the maximum distance, $h$, above the man's throwing hand that the rock will travel. Neglect air resistance.

A 65-kg hiker climbs to the second base camp on Nanga Parbat in Pakistan, at an altitude of $3900 \mathrm{~m}$, starting from the first base camp at $2200 \mathrm{~m}$. The climb is made in $5.0 \mathrm{~h}$. Calculate (b) the average power output.

You push your couch a distance of $4.00 \mathrm{~m}$ across the living room floor with a horizontal force of $200.0 \mathrm{~N}$. The force of friction is $150.0 \mathrm{~N}$. What is the work done by you, by the friction force, by gravity, and by the net force?

A piñata of mass $3.27 \mathrm{~kg}$ is attached to a string tied to a hook in the ceiling. The length of the string is $0.81 \mathrm{~m}$, and the piñata is released from rest from an initial position in which the string makes an angle of $56.5^{\circ}$ with the vertical. What is the work done by gravity by the time the string is in a vertical position for the first time?

a) If you are at the top of a toboggan run that is $40.0 \mathrm{~m}$ high, how fast will you be going at the bottom, provided you can ignore friction between the sled and the track? b) Does the steepness of the run affect how fast you will be going at the bottom? c) If you do not ignore the small friction force, does the steepness of the track affect the value of the speed at the bottom: