How to Calculate the Components of Forces and Acceleration in Physics Problems?

[vriti1D]

Homework Statement

A 525 kg boat is sailing at 4.5 m/s, east. One minute later it is sailing at 3.5m/s, 45 degrees. During this time, 3 forces act on it. Two of the forces are 25 N,78 degrees, and 32 N, 21 degrees. a) find the horizontal and vertical components of the initial and final velocity. b) find the horizontal and vertical components of the average acceleration. c) find the horizontal and vertical components of the sum of the forces. d) find the horizontal and vertical components of the missing force.

Homework Equations

Could you please help me from b to d? I think I got part a correct.

The Attempt at a Solution

a) I got vxi=4.5m/s vyi=0m/s vxf=2.47m/s vyf=2.47m/s
b)I have no idea how to find the average acceleration using any of this

 

[Simon Bridge]

a) find the horizontal and vertical components of the initial and final velocity

Huh! Well, on calm seas, the vertical components are both zero!
But you are probably correct to think the question means NS and EW components.

You should make sure by specifying where your x and y-axis points in terms of the compass.

A 525 kg boat is sailing at 4.5 m/s, east. One minute later it is sailing at 3.5m/s, 45 degrees.

OK - so we can make +y as N, and +x as E ... but is the 45degree bearing to the east or west of north?

Anyway - you seem to have been able to do (a)

For (b) ... average acceleration is given by: $$\vec{a}_{ave}=\frac{\Delta\vec{v}}{\Delta t}$$