A car crashes into a wall a 25m/s and is brought to rest in 0.1s. Calculate the average force exerted on a 75-kg test dummy by the seat belt.
What is the formula to solve this problem.
Try to think a problem through, rather than looking for an equation to post values into.
Here you need the force on the dummy, one way to calculate force is
F=ma
where m=mass and a=acceleration
the question gives you the mass of the dummy. How do we calculate the acceration from the data given?
HEHAW! BLING BLAT!
18,750
To solve this problem, we need to use Newton's second law of motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration.
The formula we will use is:
F = m * a
Where:
F is the force (in Newtons),
m is the mass (in kilograms),
a is the acceleration (in meters per second squared).
In this problem, the car crashes into a wall at a speed of 25 m/s and is brought to rest in 0.1 seconds. We can assume that the acceleration of the car is constant during this time.
First, we need to calculate the acceleration. We can use the kinematic equation:
v = u + a * t
Where:
v is final velocity (0 m/s),
u is initial velocity (25 m/s),
a is acceleration (unknown),
t is time (0.1 s).
Rearranging the equation, we have:
a = (v - u) / t
Substituting the given values:
a = (0 - 25) / 0.1
a = -250 m/s^2
Since the acceleration is negative, it means the car is decelerating.
Now that we have the acceleration, we can calculate the force exerted on the dummy using Newton's second law:
F = m * a
Substituting the given mass:
F = 75 kg * (-250 m/s^2)
F = -18,750 N
The negative sign indicates that the force is directed opposite to the motion of the car. However, for simplicity, we can ignore the negative sign and state the force as 18,750 N. Therefore, the average force exerted on the 75-kg test dummy by the seat belt is 18,750 Newtons.