Question

A car is moving at a relatively slow speed, let's say a good running speed for...

A car is moving at a relatively slow speed, let's say a good running speed for a short distance sprint, when it hits a solid wall (top figure).

The car comes to a complete stop, with a somewhat shorter front section now. The driver, who was not wearing a seat belt, tries to hold himself off the steering wheel.

Let us find the necessary average force acting on the 86-kg driver that is necessary to bring him to a complete stop before hitting the steering wheel or windshield. This is also the force the driver needs to exert on the steering wheel (Newton's 3rd Law).

The distance that is available to achieve this, as we will see impossible feat, is the original distance to the steering wheel plus the amount by which the front section shortens. For now, let's assume a probably too generous distance of 1 m.

I want you to work this out two different ways:

Use your knowledge about motion at constant acceleration to find the acceleration, and then use Newton's 2nd Law to find the magnitude of the force.

Use the Work-Kinetic Energy Theorem to find the magnitude of the force.

Of course, you should expect to get the same answer with both methods. Below answer with the force in pounds (lbs).

0 0
Add a comment Improve this question Transcribed image text
Answer #1

he b Mass -86kg distane Im () Fist 2- 86 V 2. 2- ay okn en Wok dose 2 2. 43v

Add a comment
Know the answer?
Add Answer to:
A car is moving at a relatively slow speed, let's say a good running speed for...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
  • A set of crash tests consists of running a test car moving at a speed of...

    A set of crash tests consists of running a test car moving at a speed of 12.2 m/s (26.8 m/h) into a solid wall. Strapped securely in an advanced seat belt system, a 55.0 kg (121.0 lbs) dummy is found to move a distance of 0.690 m from the moment the car touches the wall to the tíme the car is stopped. Calculáte the size of the average force which acts on the dummy during that time The force that...

  • 4. A 76-kg car driver reaches the bottom of a hill moving at a speed of...

    4. A 76-kg car driver reaches the bottom of a hill moving at a speed of v= 20 m/s. This bottom of the hill forms the arc of a circle whose radius is 200 m, as shown. (a) At this bottom of the hill, what is the magnitude /r = 200 m of the centripetal acceleration of the driver? (b) Find the force exerted on the driver by the car seat at this bottom of the hill. [(a) 2 m/s;...

  • A set of crash tests consists of running a test car moving at a speed of...

    A set of crash tests consists of running a test car moving at a speed of 10.8 m/s (23.8 m/h) into a solid wall. Strapped securely in an advanced seat belt system, a 61.0 kg (134.2 lbs) dummy is found to move a distance of 0.600 m from the moment the car touches the wall to the time the car is stopped. (a)Calculate the size of the average force which acts on the dummy during that time.(b)Using the direction of...

  • A) A set of crash tests consists of running a test car moving at a speed...

    A) A set of crash tests consists of running a test car moving at a speed of 11.8 m/s (26.0 m/h) into a solid wall. Strapped securely in an advanced seat belt system, a 57.0 kg (125.4 lbs) dummy is found to move a distance of 0.840 m from the moment the car touches the wall to the time the car is stopped. Calculate the size of the average force which acts on the dummy during that time. B) Using...

  • A car that weighs 1.4×104 N is initially moving at a speed of 50 km/h when...

    A car that weighs 1.4×104 N is initially moving at a speed of 50 km/h when the brakes are applied and the car is brought to a stop in 15 m. Assuming that the force that stops the car is constant, find the magnitude of that force. Incorrect. Tries 5/20 Previous Tries Find the time required for the change in speed. Tries 0/20 If the initial speed is, instead, twice as great, and the car experiences the same force during...

  • A box (350 kg) sits inside the trailer of a semitruck traveling at a speed of...

    A box (350 kg) sits inside the trailer of a semitruck traveling at a speed of 15 m/s (~ 33 mph). Suddenly, a car in front of the truck stops in the road. The driver of the truck hits the brakes to bring the truck to a stop. Assume that the coefficient of static friction µs = 0.7 between the box and the floor of the trailer. Assume g = 10 m/s2. When the truck is slowing down, what is...

  • 11. A car of mass m is on an icy driveway inclined at an angle 0...

    11. A car of mass m is on an icy driveway inclined at an angle 0 as shown above (a) Draw the free-body diagram for the car. (b) Write down Newton's 2ad law for the car along the two axes in your free body diagram. (c) Find the acceleration of the car (in terms of 0 and g), assuming that the driveway is frictionless. (d) Suppose the car is released from rest at the top of the incline and the...

  • 11. A car of mass m is on an icy driveway inclined at an angle 0...

    11. A car of mass m is on an icy driveway inclined at an angle 0 as shown above (a) Draw the free-body diagram for the car. (b) Write down Newton's 2ad law for the car along the two axes in your free body diagram. (c) Find the acceleration of the car (in terms of 0 and g), assuming that the driveway is frictionless. (d) Suppose the car is released from rest at the top of the incline and the...

  • O) A 1200 (kg) car has an initial speed of 27.0 () while moving over level ground. During its mot...

    o) A 1200 (kg) car has an initial speed of 27.0 () while moving over level ground. During its motion the car has a net force in the tangential direction of F 4250-3.6 v (N e of 45.0° before the curvature changes to the opposite direction, with the same radius. The car is ap proaching a hill 160 (m) away. The hill has a radius of 150 (m), and spans an 150 (m) 45.0 27.0 160 (m) Draw a FBD...

  • Consider the block arrangement for the following situations: (a) Block moving upward at constant speed (b) Block moving...

    Consider the block arrangement for the following situations: (a) Block moving upward at constant speed (b) Block moving downward at constant speed (c) Block moving upward, speed decreasing (d) Block moving upward, speed increasing (e) Block stationary it was like that i dont understand the question. help. Example 5.2.1 Sample Problem Block accelerating vertically This first figure shows a vertically moving block on the end of a cord. Example 5.2.1 Figure 1 This second figure gives the vertical velocity component...

ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT