# Homework Help: Questions about Forces

1. Feb 6, 2013

### Robertoalva

1. The problem statement, all variables and given/known data

A 1-kg object is moving in the x direction at 17.1 m/s. Just 3.75 s later, it is moving at 30.9 m/s at 30.3° to the x axis. What are the magnitude and direction of the force applied during this time?

2. Relevant equations
F=ma

3. The attempt at a solution
I have no idea on how to do this problem!

2. Feb 6, 2013

### Melon Knight

Re: Help! I Need Somebody Help!

Try approaching the problem by considering the force in the x and y directions separately. That's usually a good first approach in anything related to Newton's Laws or kinematics in my opinion.

If you can find the change in velocity in the x and y direction, you can then find the acceleration in the two directions, which would give you the force applied.

A more useful thread title and more effort on your part to attempt the problem would help you in the long run.

3. Feb 6, 2013

### Staff: Mentor

Re: Help! I Need Somebody Help!

Assume that the object is moving in the x-y (horizontal plane). Draw a picture (qualitative) showing the object location and velocity vector at times t = 0, and t = 3.75 s. What are the x- and y components of the object's velocity at time t = 0, and t = 3.75 s? This should give you some idea of what to do next.