Physics 161 Forces Homework: Calc Net Force of 340 kg Rocket Sled

[Kawasaki268F]

Homework Statement

1. A 340 kg rocket sled can be accelerated at a constant rate from rest to 1900 km/h in 2.6 s. What is the magnitude of the required net force?

Homework Equations

The Attempt at a Solution

1. So I tried calculating the acceleration and multiplying it by the mass. For the acceleration I tried dividing 1900km/h by 2.6s and multiplying it by the mass however that did not work.

 

[PeterO]

Homework Statement

1. A 340 kg rocket sled can be accelerated at a constant rate from rest to 1900 km/h in 2.6 s. What is the magnitude of the required net force?

Homework Equations

The Attempt at a Solution

1. So I tried calculating the acceleration and multiplying it by the mass. For the acceleration I tried dividing 1900km/h by 2.6s and multiplying it by the mass however that did not work.

This may sound silly, but you did convert the 1900 km/h to m/s didn't you?

 

[C268]

Yes sorry I did do that, forgot to mention that above

 

[PeterO]

Yes sorry I did do that, forgot to mention that above

Ok approximating

1900km/h is a little over 500 m/s

A little over 500 in 2.6 must be about 500 in 2.5 seconds so acceleration is around 200 ms^-2

F = ma says 200 * 340 so approx 68 000 N

What answer did you get?

 

[Kawasaki268F]

Ok approximating

1900km/h is a little over 500 m/s

A little over 500 in 2.6 must be about 500 in 2.5 seconds so acceleration is around 200 ms^-2

F = ma says 200 * 340 so approx 68 000 N

What answer did you get?

Sweet thanks! I just forgot about the squared part on 200m/s

 

[PeterO]

Sweet thanks! I just forgot about the squared part on 200m/s

Are you saying the only error you had was in the units of an answer? because none of the numbers in this problem are squared?