Summer School 2007

Front Wheel Drive Car

Edit, select all, and copy this worksheet. Open MS Word and paste this worksheet. Print it so you can follow these instructions.

Open IP5.0

Click rectangle tool. Draw rectangle and place on bottom of the screen. Click on one of the black squares on the rectangle and drag so the rectangle is as long as the screen is wide. This rectangle is the road.

Anchor it.

Draw a second rectangle. Move it so it is centered vertically, above the left end of the road. Notice on the bottom of the screen the letters h and w. This is the height and width of the rectangle. Drag the black boxes on the corners of the rectangle to make the rectangle approximately 0.5 m high and 1.5m wide. This is the body of your car.

Now go back to the road and make it 0.5m high and 6.0m wide.

We need wheels. Wheels are circles. If your picture is too small, Use the + magnifier to enlarge it. Now it will be easier to draw the objects and place them properly.

Click on the circle tool and drag one of the black boxes until the radius is 0.2m

Use cntrl, c,v to copy and paste a second wheel.

For wheels to operate properly, the center of the wheel must be attached to the body.

Move each wheel so the wheels are properly located. It should look like this.

 Both wheel must be located at the same height (y position, on bottom of screen). If they are not at the same y position, you will need to go to the Properties Window. Double click on the left wheel. The Properties Window should open.  The number in the y slot is the y position of the center of the wheel. Click on the right wheel and type in the same number as the left wheel for the y position. X out of the properties window.

Wheels must be attached to the body , yet allowed to rotate. The pin joint tool will do this. Click on the pin joint, and move to the center of the wheel. You will know you are on the center of the wheel, because a cross wheel appear. Do this for both wheels.

A car’s engine is attached to the wheels by many shafts and gears. The engine turns and each part in between turns, and finally the wheels turn. To see this, visit the automotive physics lesson in the physics lesson  in the web site. The engine applies a torque to the wheel causing it to rotate.

Click the torque tool and place it on the center of the front wheel.

Now your car is ready to  road test. Since all parts of the car are attached to each other , you can move the entire car by dragging it . Be careful not to go to the center of the car body . Clicking at the center and dragging will give the car an initial velocity . ( you will see a blue arrow) Drag the car and move it to the road. Be careful not to place it too low , so the wheels are overlapping the road. It should look like this.

Run. What is wrong?

The wheel is going backwards. (counter clockwise) Double click on the torque to open the Properties Window (or go to Window tool and open Properties, scroll down to the torque. Notice the number is 1.000. How could you change the number so the wheel will roll clockwise? (+ or -)

Run. Is that better?

Now you are going to investigate the factors that affect how fast the car goes.

To determine how fast the car is going, we need to measure the car’s velocity. Click on the car body, go to the measure button on the top of the screen, go down to velocity, choose x graph (x is the left-right direction). A graph will appear on your screen.

Run. You will see a graph of the velocity vs time.  Click twice on the arrow in the upper left corner, so the velocity will be a number.

Run. Notice the velocity value increases. The car is accelerating. We should measure the acceleration. Click on the car body, go to the measure button, and choose acceleration, x graph. Click twice on the arrow so a number will appear.

Run. The number should reach a constant value after a few seconds.

What could you change so the car will run faster?

Double click on the car body; change the mass. Run. Does the car run faster or slower? 

Double click on the torque; change the value. Run. Does the car run faster or slower? 

If you want to see a graph of the velocity data, go to Physics Activities, Physics Lessons, Tutorial 1, step 6, and proceed to make a MS Excel graph of the velocity vs time.

  Now lets make a racetrack with a ramp for the car to jump. Negative magnify the car body once. Go back to the curser, so you don’t continue to negative magnify.   Move the

Car and road to the left of the screen, so we can build a track to the right. Click on the road; drag the top, right black box to the right until the road is 16 m wide.

Ramps are triangles. Draw a triangle (use polygon tool) and place it on the road. You can use the properties window to set the y position. This will allow you to place the ramp directly road, not overlapping it.

Run.

Now draw a second ramp and place it so the picture looks like this.

  Run. Does the car make across both ramps and back to the road without trouble?  

Se my   trial 1            

 If not , make some changes , such as car mass , torque, length of road before ramp, height of ramp, space between ramps, or anything you can think of to make it work.

When you get it to work , Save as Ramp jump ,your name.

Se my best trial 2