Pam has a mass of 35.2 kg and she is at rest on smooth, level, frictionless ice. Pam straps on a rocket pack. The rocket supplies a constant force for 19.4 m and Pam acquires a speed of 63.4 m/s. What is the magnitude of the force in N?
2006-12-15 12:42:16 · 6 answers · asked by Derrick Z 1 in Science & Mathematics ➔ Physics
that's 19.4 meters, not minutes.
2006-12-15 12:54:41 · update #1
By definition,
s = v(mean) × t
v(mean) = (v + v') /2
a = (v - v')/t,
where v' denotes initial velocity. From here,
as = (v +v')t/2 × (v - v')/t = ½(v² - v'²), or
2as = v² - v'²
Since Pam is initially at rest, v' = 0. From the above eq.,
a = v²/2s = 103.6 m/s²
From Newton's 2nd Law, f = ma = 35.2 × 103.6 = 3 647 N.
Poor Pam. She never had a chance to recover from being subject to such brutal acceleration (10.6 g!). May she rest in heaven in peace forever!
2006-12-15 13:10:44 · answer #1 · answered by Jicotillo 6 · 2⤊ 0⤋
63.4m/s has a counter force that slowes it down by the weight of pam which is 35.2 kg but guess what the weight doesn't matter because its calculated with her weight so she is going 63.4m/s. into some ivisible wall that is right in front of her. I know I'm kinda dumb when it comes to somethings like this but I hope what I said can help out some. but I do know that if there is no friction and her weight is added when the calculated the speed that there is nothing slowing it down except gravity itself.
forget it I'm just running my mouth about something I don't even know. sorry Good god that guy above me is smart, but he's right so go for him, I vote him as best answer.
2006-12-15 20:53:20 · answer #2 · answered by eclipsefreak 4 · 0⤊ 0⤋
a = (v^2 - v0^2)/(2s)
a = (63.4^2 - 0^2)/(2*19.4)
a = 4,019.56/38.8
a = 103.6 m/s^2,
which does, indeed, kill Pam without our learning the force applied, since we don't know the mass of the rocket pack, which must be significant in order to produce such a large thrust.
(actually, F = mdv/dt + vdm/dt = mvdv/ds + v^2 dm/ds)
The approximate net force on Pam is 3,647 N
2006-12-16 00:50:08 · answer #3 · answered by Helmut 7 · 1⤊ 0⤋
Yes, I can.
First, you need to find the acceleration for Pam from 0 m/s to 63.4 m/s. You already have time : 19.4 minutes, this equals to 19.4 min *( 60sec/1min) = 1164 sec.
a = (v - v0)/t = (63.4m/s - 0m/s) / 1164 s = 0.05446754 m/s2
Then, You find F. F=ma
F = ma = (35.2 kg) * (0.05446754) = 1.92 N
Answer is 1.92 N. Vote for me !
2006-12-15 20:52:31 · answer #4 · answered by Anonymous · 3⤊ 1⤋
F=ma
You've got the mass and need acceleration.
From the first part, you have that she started at 0m/s and traveled 19.4m obtaining a speed of 63.4m/s .
Look for an equation where you can solve for acceleration given x (distance traveled) and velocity.
Then plug that in to f=ma
2006-12-15 20:50:22 · answer #5 · answered by bkc99xx 6 · 0⤊ 0⤋
Your question is unclear. Thanh is correct if 19.4 = 19.4 minutes. But when I first read the question I thought it was 19.4 meters. Please clarify.
2006-12-15 20:56:43 · answer #6 · answered by dgbaley27 3 · 0⤊ 0⤋