A person who is properly constrained by an over-the-shoulder seat belt has a good chance of surviving a car collision if the deceleration does not exceed about 30 "'s".
Assuming uniform deceleration of this value, calculate the distance over which the front end of the car must be designed to collapse if a crash brings the car to rest from 85
A ball is tossed vertically upward from the ground and caught at a height of 15m. After 1.85seconds.
a)what is the velocity with which it was throuwn?
b)What maximum height does it reach.
c)whatt was the velocity when it was caught?
A person who is properly constrained by an over-the-shoulder seat belt has a good chance of surviving a car collision if the deceleration does not exceed about 30 "'s".
Assuming uniform deceleration of this value, calculate the distance over which the front end of the car must be designed to collapse if a crash brings the car to rest from 85.
can you please help me am stuck
Since we want our units to be in meters and seconds, lets first convert 85 km/hr to m/s.
85 km 1000 m 1 hr
---------- x ------------- x -------------- = 23.61 m/s
1 hr 1 km 3600 sec
Next, lets convert the 30 "g's" to m/s^2, knowing that 1.0 g = 9.8 m/s^2
30 g 9.8 m/s^2
-------- x --------------- = 294 m/s^2
1 1 g
Now lets fill in the variables we know:
Initial velocity (Vo) = 23.61 m/s
End velocity (V) = 0 m/s (since the car has stopped at this point)
Initial position (Xo) = 0 m
End position (X) = ?
Acceleration (a) = -294 m/s^2 (The # is negative since we are decelerating)
Now all we have to do is plug our variables into an equation to find our end position. For this we will use the following equation and complete the following steps:
V^2 = Vo^2 + 2a(x-xo)
0 = (23.61)^2 + 2(-294) (X-0)
0 = 557.48 - 588x
-557.48 = -588x
x = 0.95 m
So our answer is that the car needs to be designed to go 0.95 m. Hopefully this helps!
To calculate the distance over which the front end of the car must be designed to collapse, we can use the formula for deceleration:
Deceleration = (Final Velocity - Initial Velocity) / Time
Here, the initial velocity is the speed of the car before the crash (85 "s") and the final velocity is 0 (since the car comes to rest). We don't have the time, so we need to calculate it.
Using the equation of motion for uniform acceleration:
Final Velocity^2 = Initial Velocity^2 + 2 * Acceleration * Distance
Since the final velocity is 0 and the acceleration is -30 "s", we can rearrange the equation to solve for distance:
Distance = (Final Velocity^2 - Initial Velocity^2) / (2 * Acceleration)
Plugging in the values and doing the calculations:
Distance = (0^2 - 85^2) / (2 * -30 "s")
Distance = (0 - 7225) / (-60 "s")
Distance = 7225 / 60 "s"
Distance ≈ 120.42 "s"
Therefore, the front end of the car must be designed to collapse over a distance of approximately 120.42 "s" in order to bring the car to rest from a speed of 85 "s".
vf^2=vi^2+2ad
for a,30*9.8 m/s^2; vf=0, vi= convert to m/s
solve for d