A car leaves the road traveling at 110 km/h and hits a tree, coming to a stop in 0.14 s. What average force does a seatbelt exert on a 60-kg passenger during this collision? Wolfson, richard. Essential university physics, volume 1 (page 67). Pearson education. Kindle edition.

Respuesta :

We use the Newtons law,

[tex]F=m a[/tex]                        (A)

Equation of motion,

[tex]v = u + at[/tex]                   (B)

Here, v is final velocity , u is initial velocity and a is acceleration.

Given  [tex]u = 110 \ km/h = 110 \frac{10^3 m}{60 \times 60 \ s} =30.55 \ m/s, t = 0.14 s[/tex] .

As car coming to stop, so final velocity becomes zero i.e  [tex]v = 0[/tex].

Substituting these values in equation (B), we get

[tex]0 = 33 . 55 \ m/s + a (0.14 \ s ) \\\\ a = \frac{ (-33.50 m/s )}{0.14 s } =- 239 .64   \ m/s^2[/tex]

Here, negative sign means, deceleration to rest.

As given the mass of passenger, m = 60 kg.

Therefore, from equation (A),

[tex]F = (60 kg) (-239 .64 \ m/s^2) = -14378.57 N[/tex]

Thus , the force seat belt exert on the passenger during the collision is [tex]-14378.57 \ N[/tex]