A car can stop from60mph in 2.5 sec. If the car has a weight of 3225 lbs what force acts on the car?
Acceleration is change in velocity over time, or:
a = (v2 - v1)/t
Initial velocity (v1) and time (t) is given, and final velocity (v2) is zero since it eventually comes to rest.
Convert first the initial velocity units to ft/s, then solve for acceleration. Finally, substitute it to formula for force.
Force is mass x acceleration, or:
F = m*a
The mass (m) is given so you can solve for force.
Units of force in lb,m ft/s^2
60mph converts into 26.82m/s,
a= (0-26.82 m/s)
-26.82 m/s
but don't understand how to get answer in Newtons which are kg m/s^2
a = (Vf-Vi)/t = -26.82m/s / 2.5s = -10/73 m/s^2
Now recall F=ma
oops. That's -10.73, not 10/73
To determine the force acting on the car, we can use Newton's second law of motion, which states that the force acting on an object is equal to its mass multiplied by its acceleration.
First, we need to convert the weight of the car from pounds to mass. We can do this by dividing the weight by the acceleration due to gravity (approximately 32.2 ft/s^2 for Earth).
So, mass (in slugs) = weight (in pounds) / acceleration due to gravity (32.2 ft/s^2)
Mass = 3225 lbs / 32.2 ft/s^2 = 100 slugs (approximately)
Next, we need to convert the stopping distance from mph to ft/s. We know that 1 mph is equal to 1.4684 ft/s. Therefore, 60 mph is equal to 60 * 1.4684 ft/s = 88.1 ft/s (approximately).
Now, we can calculate the deceleration (negative acceleration) of the car using the equation:
Deceleration = Change in velocity / Time taken
= 88.1 ft/s / 2.5 sec
= 35.24 ft/s^2 (approximately)
Finally, we can find the force acting on the car using Newton's second law:
Force = Mass * Acceleration
= 100 slugs * 35.24 ft/s^2
= 3524 lb-ft/s^2 (approximately)
Note that the unit of force in this case is pound-force (lb-ft/s^2) due to using slugs as the unit for mass.