A sled, with mass $m$, is given a shove up a frictionless incline, which makes a $28.0^{\circ}$ angle with the horizontal. Eventually, the sled comes to a stop at a height of $1.35 \mathrm{~m}$ above where it started. Calculate its initial speed.

A car of mass $m=1250 \mathrm{~kg}$ is traveling at a speed of $v_0=105 \mathrm{~km} / \mathrm{h}$ $(29.2 \mathrm{~m} / \mathrm{s})$. Calculate the work that must be done by the brakes to completely stop the car.

How much work is done when a $75.0-\mathrm{kg}$ person climbs a flight of stairs $10.0 \mathrm{~m}$ high at constant speed? a) $7.36 \cdot 10^5 \mathrm{~J}$, b) $750 \mathrm{~J}$, c) $75 \mathrm{~J}$, d) $7500 \mathrm{~J}$, e) $7360 \mathrm{~J}$.

An advertisement claims that a certain $1200 .-\mathrm{kg}$ car can accelerate from rest to a speed of $25.0 \mathrm{~m} / \mathrm{s}$ in $8.00 \mathrm{~s}$. What average power must the motor supply in order to cause this acceleration? Ignore losses due to friction.

A shot-putter accelerates a 7.30-kg shot from rest to $14.0 \mathrm{~m} / \mathrm{s}$. If this motion takes $2.00 \mathrm{~s}$, what average power was supplied?

A certain tractor is capable of pulling with a steady force of $14.0 \mathrm{kN}$ while moving at a speed of $3.00 \mathrm{~m} / \mathrm{s}$. How much power in kilowatts and in horsepower is the tractor delivering under these conditions?

How much work is done against gravity in lifting a 6.00-kg weight through a distance of $20.0 \mathrm{~cm}$ ?

At the 2004 Olympic Games in Athens, Greece, the Iranian athlete Hossein Rezazadeh won the super-heavyweight class gold medal in weightlifting. He lifted $472.5 \mathrm{~kg}$ (1042 lb) combined in his two best lifts in the competition. Assuming that he lifted the weights a height of $196.7 \mathrm{~cm}$, what work did he do?

A car of mass $m$ accelerates from rest along a level straight track, not at a constant acceleration but with constant engine power, $P$. Assume that air resistance is negligible. c) You are in a drag race, on a straight level track, with an opponent whose car maintains a constant acceleration of $12.0 \mathrm{~m} / \mathrm{s}^2$. Both cars have identical masses of 1000 . kg. The cars start together from rest. Air resistance is assumed to be negligible. Calculate the minimum power your engine needs for you to win the race, assuming the power output is constant and the distance to the finish line is $0.250 \mathrm{mi}$.

A car of mass $m$ accelerates from rest along a level straight track, not at a constant acceleration but with constant engine power, $P$. Assume that air resistance is negligible. b) A second car starts from rest alongside the first car on the same track, but maintains a constant acceleration. Which car takes the initial lead? Does the other car overtake it? If yes, write a formula for the distance from the starting point at which this happens.

A car of mass $m$ accelerates from rest along a level straight track, not at a constant acceleration but with constant engine power, $P$. Assume that air resistance is negligible. a) Find the car's velocity as a function of time.

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 car of mass $942.4 \mathrm{~kg}$ accelerates from rest with a constant power output of $140.5 \mathrm{hp}$. Neglecting air resistance, what is the speed of the car after $4.55 \mathrm{~s}$ ?

An engine expends $40.0 \mathrm{hp}$ in moving a car along a level track at a speed of $15.0 \mathrm{~m} / \mathrm{s}$. How large is the total force acting on the car in the direction opposite to the motion of the car?