Mass of Object Pulled by 40 HP Engine: 1,350 Kg

[Pao44445]

Homework Statement

Find the mass of the object which is being pulled by 40 hp engine with a constant speed 15 m/s (μ = 0.15)

Homework Equations

P=Fv
F=μN

The Attempt at a Solution

I got about 1,350 Kg for the answer but I don't know why P=Fv( It is just included in the problem )
First, I tried to figure how much force do I need to pull this object with P=Fv.
29,840 J/s=F(15 m/s)
I got F about 1940 N
Now, I knew that I need 1940 N to pull this object, I use ΣF(system)=F(being pull)-F(friction)
1940 N = (m)(a)-(μ)(m)(g)
1940 N = 0-(0.15)(m)(9.8)
m≈-1,350 Kg but a mass cannot be negative so the answer is 1,350 Kg

 

[SteamKing]

Homework Statement

Find the mass of the object which is being pulled by 40 hp engine with a constant speed 15 m/s (μ = 0.15)

Homework Equations

P=Fv
F=μN

The Attempt at a Solution

I got about 1,350 Kg for the answer but I don't know why P=Fv( It is just included in the problem )
First, I tried to figure how much force do I need to pull this object with P=Fv.
29,840 J/s=F(15 m/s)
I got F about 1940 N
Now, I knew that I need 1940 N to pull this object, I use ΣF(system)=F(being pull)-F(friction)
1940 N = (m)(a)-(μ)(m)(g)
1940 N = 0-(0.15)(m)(9.8)
m≈-1,350 Kg but a mass cannot be negative so the answer is 1,350 Kg

You should draw a diagram for this problem.

The tension in the rope which is doing the pulling is counteracted by friction. Your F(being pull) ≠ (m)(a), since a = 0 yet F(being pull) must be > 0.