Solving vectors using trigonometric method  TOPIC_SOLVED

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Solving vectors using trigonometric method

Postby gierose on Wed Jun 24, 2009 1:15 pm

A car weighing 12.0kg (2700lbs) is parked on a driveway that is at 15 degree angle with the horizontal. Find the components of the car's weight parallel and perpendicular to the driveway?

A woman on the ground sees an airplane climbing at an angle of 35 degrees above the horizontal. She gets into her car and by driving at 70 mi/h is able to stay directly below the airplane. What is the airplane speed?

please help me with these problems! i don't get them. :confused:
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Postby stapel_eliz on Wed Jun 24, 2009 3:37 pm

Since you didn't show any work, I'll guess that you need help getting started.

gierose wrote:A car weighing 12.0kg (2700lbs) is parked on a driveway that is at 15 degree angle with the horizontal. Find the components of the car's weight parallel and perpendicular to the driveway?

Draw the right triangle representing the driveway (one leg), the perpendicular (the other leg), and the base. The right angle is where the car is. Draw the height line, being perpendicular to the base; the height of the right triangle is 12. (I think this may be a typo, though; 12 kilograms does not correspond to 2700 pounds.)

The height line forms two right triangles, with the legs of the original triangles being the hypotenuse of each new triangle. Use trig ratios and the given angle measure to find their lengths.

gierose wrote:A woman on the ground sees an airplane climbing at an angle of 35 degrees above the horizontal. She gets into her car and by driving at 70 mi/h is able to stay directly below the airplane. What is the airplane speed?

Draw the right triangle formed by the height, the ground, and the path of the plane. Label the base angle with the given value, and the base with "70". Use trig ratios to find the value of the hypotenuse.

If you get stuck, please reply showing your steps and reasoning so far. Thank you! :wink:
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