How Much Force Does Pam's Rocket Pack Generate?

[Iceclover]

Homework Statement

Pam has a mass of 40.0kg and she is at rest on a smooth level frictionless ice. pam straps on a rocket pack. the rocket pack supplies a constant force for 22.0m and pam acquires a speed of 62.0m/s

a)what is the magnitude of the force?
b)what is pams final kinetic energy

Homework Equations

a)F=mg
b)Ek=1/2mv^2

The Attempt at a Solution

a)
m=40.0kg
d=22.0m
v=62.0m/s
F=mg
F=(40.0)(9.8)
F=392N

b)
m=40.0
v=62.0
Ek=?
Ek=1/2mv^2
Ek=1/2(40.0)(62.0^2)
Ek=7.69x10^4J

 

[cristo]

Homework Statement

Pam has a mass of 40.0kg and she is at rest on a smooth level frictionless ice. pam straps on a rocket pack. the rocket pack supplies a constant force for 22.0m and pam acquires a speed of 62.0m/s

a)what is the magnitude of the force?
b)what is pams final kinetic energy

Homework Equations

a)F=mg
b)Ek=1/2mv^2

The Attempt at a Solution

a)
m=40.0kg
d=22.0m
v=62.0m/s
F=mg
F=(40.0)(9.8)
F=392N

This is not the force you were asked for: this is the weight of the person. Try using the relevant kinematic equation to calculate the acceleration, then use Newtons 2nd law to work out the force.

b)
m=40.0
v=62.0
Ek=?
Ek=1/2mv^2
Ek=1/2(40.0)(62.0^2)
Ek=7.69x10^4J

This looks fine

 

[Iceclover]

how do i figure out the acceleration without the force?

 

[Iceclover]

wow i definitely did not do this right, i got 3480

 

[cristo]

how do i figure out the acceleration without the force?

Using the kinematic equations [hint: the relevant one to use here is v²=u²+2as, where here v is the final velocity, u is the initial velocity, a is acceleration and s is the distance.]

 

[cristo]

wow i definitely did not do this right, i got 3480

I get 3495N

 

[Iceclover]

i got 3520

 

[Iceclover]

ok so if you put it into sig figs you would get 3.5x10^3

 

[cristo]

ok so if you put it into sig figs you would get 3.5x10^3

Yes, if you're using 2sf.

 

[Iceclover]

ok so that's right then?