Trouble finding the magnitude of a net force required.

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SUMMARY

The discussion centers on calculating the net force required to accelerate an 800 kg rocket sled from rest to 1500 km/h in 2.1 seconds. The user initially misinterpreted the final velocity of 416.7 m/s as acceleration, leading to an incorrect force calculation using F=ma, resulting in 333360 N. Upon clarification, the user recognized that the correct acceleration must be derived from the change in velocity over time, which is essential for accurate force computation.

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  • Understanding of Newton's Second Law (F=ma)
  • Basic knowledge of kinematics, specifically velocity and acceleration
  • Ability to convert units, particularly from km/h to m/s
  • Familiarity with the concept of net force in physics
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  • Calculate acceleration using the formula a = (final velocity - initial velocity) / time
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mcaustin
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Here is the problem I have:
1. A 800 kg rocket sled can be accelerated at a constant rate from rest to 1500 km/h in 2.1 s. What is the magnitude of the required net force?

First I converted the a from 1500 km/h to 416.7 m/s
I then used F=ma but I got the result as 333360 N but this answer is incorrect. I'm not quite sure where to go from here and I don't know what the significance of time is. I used it to calculate velocity using v=at and got 875.07 m/s but I don't know how is should use it, if at all.

Thanks for any help anyone can give!
 
Physics news on Phys.org
I figured out my mistake!
I thought that 416.7 was acceleration but it is actually velocity.
 

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