A car of mass 1250 kg starts from rest with a net force of 2750 N on it.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A car of mass starts from rest with a net force of on it.
- What is its acceleration?
- How long does it take to reach , which is about ?
Need a reminder? The key ideaShow
Newton's second law. The net force on a body equals its mass times its acceleration:
Then the equations of motion follow: and .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. , , , .
Plan. The second law gives ; then .
Step 1. Acceleration. .
Step 2. Time. .
Answer: (a) . (b) .
Check. About from to is typical of a family car.
Watch out. The force here is the net force. The engine's push must be bigger, to beat friction and air drag too.
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