How Do You Solve Newton's Laws Problems for a Sailboat and a Pickup Truck?

[Alethia]

Okay, in my class we've been learning basic problems solved by applying Newton's laws. I understand the general idea, but I get confused with problems like the first one. How would I solve it taking both forces on it into account? On the second problem, I don't know how to solve it because it gives you velocity and none of the formulas have velocity in it. Do I have to refer to other formula's first and then convert? Any explanation or help would be very much appreciated. Please provide a step-by-step guide so that I can teach myself. THANK YOU.

1) A sailboat with a mass of 2.0x10^3kg experiences a tidal force of 3.0x10^3N directed to the east and a wind force against its sails with a magnitude of 6.0x10^3N directed towards the northwest (45 degrees North of West). What is the magnitude of the resultant acceleration of the boat?

2) A crate is carried in a pickup truck traveling horizontaklly at 15.0m/s. The truck applies the brakes for a distance of 28.7m while stopping with uniform acceleration. What is the coefficient of static friction between the crate and the truck bed if the crate does not slide?

Thanks again for any help, and sorry to inconvienence anyone.

 

[Alethia]

I don't understand what you did for the first problem. By following your explanation I got the answer of 268.3 which is not the correct answer. =1

I understand how to solve for acceleration using that problem, but how then would I find the frictional force?

 

[Alethia]

When you say 6/(sqrt)2 does that mean 6 squared?

Originally posted by Ambitwistor
The net force is the frictional force, so you just multiply the net acceleration by m.

m as in mass? There is no mass given...