Physics

posted by .

there's three parts, i keep getting these wrong please help.

A set of crash tests consists of running a test car moving at a speed of 11.8 m/s (26.4 mi/hr) into a solid wall. Strapped securely in an advanced seat belt system, a 59.0 kg (130 lbs) dummy is found to move a distance of 0.660 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.

Using the direction of motion as the positive direction, calculate the average acceleration of the dummy during that time (in g's, with 1g = 9.81m/s2).


In a different car, the distance the dummy moves while being stopped is reduced from 0.660 m to 0.210 m,
calculate the average force on the dummy as that car stops.

  • Physics -

    (Average belt force)x (distnce moved)
    = initial kinetic energy of dummy
    = (1/2)*59 kg* (11.8 m/s)^2 = 4108 J
    Avg. Force = 4108/.66 = 6224 Newtons

    Acceleration is backwards (negative sign) and equals the speed change divided by time intervsl
    sqrt (-2aX) = V
    a = -V^2/(2X) = -105.5 m/s^2
    = -10.75 g's

    Repeat the same method for the second case. The force must be larger to stop in a reduced distance

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Science - Physics

    How can I investigate what happens to the occupants of a car when the car is in a collision in which it collides head on with a solid object (in my example, it will be a brick), and when a stationary car is hit from behind by a moving …
  2. physics

    A set of crash tests consists of running a test car moving at a speed of 11.6 m/s (25.5 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 0.750 m from …
  3. 10 grade

    A 80 slug car runs into a wall while moving at 10ft/s. If the car bounces off the wall with the same speed it struck it with as a result of having been in contact with the wall for .8 second, then find... a)... The initial momentum …
  4. physics

    A set of crash tests consists of running a test car, moving at a speed of 12.80 m/s into a solid wall. Strapped securely in an advanced seat belt system, a 63.00 kg dummy is found to move a distance of 0.690 m from the moment the car …
  5. physics

    a) A set of crash tests consists of running a test car moving at a speed of 12.6 m/s (27.7 m/h) into a solid wall. Strapped securely in an advanced seat belt system, a 69.0 kg (151.8 lbs) dummy is found to move a distance of 0.600 …
  6. tax income

    To be a qualifying child, the taxpayer must meet three general tests and five specific tests. What are the three general tests?
  7. Physics

    Which results in a higher force of impact?
  8. Physics

    Which results in a higher force of impact?
  9. Physics

    A set of crash tests consists of running a test car moving at a speed of 12.2 m/s (27.3 mi/hr) into a solid wall. Strapped securely in an advanced seat belt system, a 75.0 kg (165 lbs) dummy is found to move a distance of 0.630 m from …
  10. physics

    A set of crash tests consists of running a test car moving at a speed of 11.6 m/s (25.52 m/h) into a solid wall. Strapped securely in an advanced seat belt system, a 61 kg (134.2 lbs) dummy is found to move a distance of 0.69 m from …

More Similar Questions