G forces

Calculate deceleration of car (as multiple of gravitational acceleration g = 9.81 m/s²) which occurs when a car in a frontal collision slows down uniformly from a speed 111 km/h to 0 km/h in 1.2 meters trajectory.

Result

G =  40.4 g

Solution:

$s = \dfrac12at^2 = 1.2 \ m \ \\ 2s = at^2 \ \\ \ \\ a = \dfrac{\Delta v }{ \Delta t} \ \\ \ \\ v = at = \dfrac{2 s}{t} = 111 \ km/h = 30.833 \ m/s \ \\ \ \\ t = \dfrac{2s}{v} = \dfrac{2 \cdot 1.2}{ 30.833 } = 0.0778378 \ s \ \\ a = v / t= 30.833 / 0.0778378 = 396.123 \ m/s^2 \ \\ G = a/g = 40.4 \ \text{g}$

Try another example

Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments:

Be the first to comment!

Next similar math problems:

1. Circular motion
   Mass point moves moves uniformly in a circle with radius r = 3.4 m angular velocity ω = 3.6 rad/s. Calculate the period, frequency, and the centripetal acceleration of this movement.
2. Wavelength
   Calculate the wavelength of the tone frequency 11 kHz if the sound travels at speeds of 343 m/s.
3. Brakes of a car
   For the brakes of a passenger car to be effective, it is prescribed that a car moving on a horizontal road at a speed of 40 km. A car must stop on the track 15.4 m. What is the deceleration of the car?
4. Free fall
   How long does the stone fall freely into a depth of 80m? What speed will it hit the bottom of the abyss?
5. Shot
   Shot with a mass 43 g flying at 256 m/s penetrates into the wood to a depth 25 cm. What is the average force of resistance of wood?
6. Skid friction
   Find the smallest coefficient of skid friction between the car tires and the road so that the car can drive at a 200 m radius at 108 km/h and does not skid.
7. Brakes
   The braking efficiency of a passenger car is required to stop at 12.5 m at an initial speed of 40 km/h. What is the acceleration braking by brakes?
8. Overload
   What overload in g (g-force) has passed the pilot if he accelerated from 0 to 600 km/h in 3 seconds?
9. Abyss
   Stone was pushed into the abyss: 2 seconds after we heard hitting the bottom. How deep is the abyss (neglecting air resistance)? (gravitational acceleration g = 9.81 m/s² and the speed of sound in air v = 343 m/s)
10. Flywheel
    Flywheel turns 450 rev/min (RPM). Determine the magnitude of the normal acceleration of the flywheel point which are at a distance of 10 cm from the rotation axis.
11. Gravitation
    From the top of the 80m high tower, the body is thrown horizontally with an initial speed of 15 m/s. At what time and at what distance from the foot of the tower does the body hit the horizontal surface of the Earth? (use g = 10 ms-2)
12. Free fall
    The free fall body has gone 10m in the last 0.5s. Find the body speed at the moment of impact.
13. Bomber
    The aircraft flies at an altitude of 4100 m above the ground at speed 777 km/h. At what horizontal distance from the point B should be release any body from the aircraft body to fall into point B? (g = 9.81 m/s²)
14. Train 2
    The train slowed down from 90 km/h to 72 km/h in 5 seconds. How long track travel?
15. Theorem prove
    We want to prove the sentence: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?
16. A particle
    A particle moves in a straight line so that its velocity (m/s) at time t seconds is given by v(t) = 3t²-4t-4, t>0. Initially the particle is 8 meters to the right of a fixed origin. After how many seconds is the particle at the origin?
17. Five harvests
    In the seed company, they know that, out of 100 grains of a new variety, they get an average of 2000 grains after harvest. Approximately how many grains do they get out of 100 grains after five harvests?