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 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?

Which of the following is a correct unit of power? a) $\mathrm{kg} \mathrm{m} / \mathrm{s}^2$, b) $\mathrm{N}$, c) $J$, d) $\mathrm{m} / \mathrm{s}^2$, e) $W$.

Is each of the following statements true or false? c) A force is required to do work.

Is each of the following statements true or false? b) More power is required to lift a box slowly than to lift a box quickly.

Is each of the following statements true or false? a) Work cannot be done in the absence of motion.

A car of mass 1214.5 kg is moving at a speed of 62.5 mph when it misses a curve in the road and hits a bridge piling. If the car comes to rest in 0.236 s, how much average power (in watts) is expended in this interval?

While a boat is being towed at a speed of $12.0 \mathrm{~m} / \mathrm{s}$, the tension in the towline is $6.00 \mathrm{kN}$. What is the power supplied to the boat through the towline?

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?

A spring with a spring constant of $238.5 \mathrm{~N} / \mathrm{m}$ is compressed by $0.231 \mathrm{~m}$. Then a steel ball bearing of mass $0.0413 \mathrm{~kg}$ is put against the end of the spring, and the spring is released. What is the speed of the ball bearing right after it loses contact with the spring? (The ball bearing will come off the spring exactly as the spring returns to its equilibrium position. Assume that the mass of the spring can be neglected.)

A spring with spring constant $k$ is initially compressed a distance $x_0$ from its equilibrium length. After returning to its equilibrium position, the spring is then stretched a distance $x_0$ from that position. What is the ratio of the work that needs to be done on the spring in the stretching to the work done in the compressing?

A spring is stretched 5.00 cm from its equilibrium position. If this stretching requires 30.0 J of work, what is the spring constant?