Question

Sam's job at the amusement park is to slow down and bring to a stop the boats in the log ride. You may want to review ( pages 293 - 295) . Part A If a boat and its riders have a mass of 1200 kg and the boat drifts in at 1.2 m/s how much work does Sam do to stop it?

Answer 1

The work that Sam should do in order to stop is the boat is the same as that of the kinetic energy of the object in order to counter its motion. Kinetic energy is calculated through the equation,
                           KE = 0.5mv²
where KE is kinetic energy, m is mass, and v is the velocity.
Substituting,
                         KE = 0.5(1200kg)(1.2 m/s)²
                            KE = 864 J

Answer 2

The amount of work done by Sam to stop the boat is $\boxed{864\,{\text{J}}}$ .

Further Explanation:

Given:

The mass of the boat with all the riders is $1200\,{\text{kg}}$ .

The speed of the boat is $1.2\,{{\text{m}}\mathord{\left/{\vphantom{{\text{m}}{\text{s}}}} \right\kern-\nulldelimiterspace}{\text{s}}}$ .

Concept:

Since the boat is drifting with some speed at some point of time, the complete energy of the boat is considered to be stored in the form of its kinetic energy. Therefore, Sam needs to put in work equal to the amount of the kinetic energy of the boat to bring it to rest.

The kinetic energy of a body is the amount of energy stored in the body by virtue of its motion. Mathematically it is shown as:

$KE=\frac{1}{2}m{v^2}$

Here, $KE$  is the kinetic energy stored in the boat, $m$   is the mass of the boat and $v$  is the speed of the boat.

Substitute the values of  $m$ and $v$  in above expression.

$\begin{aligned}KE&=\frac{1}{2}\times1200\times{\left( {1.2}\right)^2}\\&=\frac{{1728}}{2}\,{\text{J}}\\&=8{\text{64}}\,{\text{J}}\\\end{aligned}$

Now, the amount of work required to stop the boat is equal to the kinetic energy of the boat.

$\begin{aligned}W&=KE\\&=864\,{\text{J}}\\\end{aligned}$

Thus, the amount of work done to bring the boat to rest is $\boxed{864\,{\text{J}}}$ .

Learn More:

1. A remote-controlled car is moving in a vacant parking lot brainly.com/question/2005478

2. A 50-kg meteorite moving at 1000 m/s strikes earth brainly.com/question/6536722

3. You are riding on a roller coaster that starts from rest at a height of 25.0 m brainly.com/question/9719731

Answer Details:

Grade: High School

Subject: Physics

Chapter: Conservation of Energy

Keywords:

Boat, Sam, mass of boat, all riders, 1200 kg, kinetic energy of  boat, 1.2m/s, work done, 864 J, stop, amusement park, slow down.