Asked by Rash

In the amusement park ride known as Magic Mountain Superman, powerful magnets accelerate a car and its riders from rest to 45 m/s (about 100 mi/h) in a time of 7.0 s. The combined mass of the car and riders is 5.5 × 103 kg. Find the average net force exerted on the car and riders by the magnets.

I've got an estimated answer of 35357.135N but I have doubts about this answer. Am I correct?
Answered by bobpursley
force=mass*acc=5.5e4*45/5=not your answer.
Answered by scott
also , be aware of SIGNIFICANT FIGURES
Answered by Rash
How am I incorrect though? I've used a kinematics equation v=vo+at, which resulted in me getting my acceleration and plugged in Newton's 2nd law as well as multiplying the acceleration by the given mass, resulting in an answer similar to this, only I believe that I may have made a round-off error on one of the two attempts.
Answered by Rash
Let me show my process:

v= 45 m/s
vo= 0 m/s
t= 7.0 s
m = 5.5 x 10^3 kg
a=?
F=?

To solve for acceleration, I've used a kinematics equation:

v=vo+at

a= (45 m/s) / (7.0 s) = 6.428 m/s^2

Then we use Newton's 2nd law:

F=ma
F= (5.5 x 10^3 kg)(6.428 m/s^2)
F is estimated to be 35354 N
Answered by bobpursley
your answer is better than mine, I read the mass as 5.5e4, not 5.5e3 as stated. Misread. Significant figures should be 2 places.
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