Question

A car is traveling at 25 m/s when an accident occurs. The car decelerates 300 m/s2 but the passenger does not slow down because he is not wearing a seatbelt. (a) Supposing the distance between the passenger and the dashboard is initially 0.50 m, what will be the speed of the car at the instant the passenger impacts the dash?

The answer is 7.7m/s but I don't understand why... @Abhisar

Answer 1

Can u show me ur work ?

Answer 2

or what answer are u getting ?

Answer 3

Since both passenger and car is travelling with 25 m/s. Velocity of car with respect to the passenger will be 0 m/s

Answer 4

After collision the car starts decelerating with 300 m/s^2. So, u=0,a=300 and s=.50

Using \(\sf v^2-u^2 + 2as\), v will be equal to -17.32 m/s. This velocity is relative to that of passenger. Actual velocity will be equal to -17.32+25=7.7 m/s

Answer 5

Got it ?

Answer 6

Negative sign in -17.32 shows that the car is basically accelerated in opposite direction to the motion of passenger.[and in actual it's decelerated]