A car weighs 15000-N and is traveling along a highway at 27 m/s. If the driver immediately applies his brakes and the car
comes to rest in 85 m, what net force acts on the car during its acceleration? How do you solve this to get an answer of -6564N?
Thanks!
Physics is the Laws of Nature, formed in the beginning of time. You hate them? Odd.
force=ma The great Issac Newton's second law of motion.
force= mass*a
but Vf^2=Vi^2+2a*d
you know Vf, Vi, and distance d. Find acceleration a, put it in the F=ma equation.
To find the net force acting on the car during its acceleration, you can use Newton's second law of motion, which states that the net force acting on an object is equal to the product of its mass and acceleration:
Net force (F_net) = mass (m) × acceleration (a)
In this case, you are given the weight of the car, which is the force due to gravity acting on it. The weight of an object can be calculated by multiplying its mass (m) by the acceleration due to gravity (g), which is approximately 9.8 m/s² on Earth. So, weight (W) can be calculated as:
Weight (W) = mass (m) × acceleration due to gravity (g)
Since weight is a force, its SI unit is Newton (N). Therefore, in this case:
Weight (W) = 15000 N
Now, to find the mass of the car, you can divide the weight by the acceleration due to gravity:
mass (m) = Weight (W) / acceleration due to gravity (g)
mass (m) = 15000 N / 9.8 m/s²
mass (m) ≈ 1530.61 kg
Next, you need to find the acceleration of the car. You know that the car starts at a speed of 27 m/s and comes to rest in 85 m. The final velocity (v) is 0 m/s, and the displacement (s) is 85 m. You can use the following equation of motion to find the acceleration:
v² = u² + 2as
Where:
v = final velocity (0 m/s)
u = initial velocity (27 m/s)
a = acceleration (to be calculated)
s = displacement (85 m)
Substituting the known values, the equation becomes:
0² = 27² + 2a(85)
Simplifying:
0 = 729 + 170a
170a = -729
a ≈ -4.29 m/s²
Now, you can find the net force by using Newton's second law of motion:
F_net = m × a
F_net = 1530.61 kg × -4.29 m/s²
F_net ≈ -6563.69 N
Therefore, the net force acting on the car during its acceleration is approximately -6564 N (rounded to the nearest whole number). The negative sign indicates that the force acts in the opposite direction to the motion of the car.