Question

A team of eight dogs pulls a sled with waxed wood runners on wet snow (mush!). The dogs have average masses of 18.5 kg, and the loaded sled with its rider has a mass of 250 kg.

(a) Calculate the acceleration of the dogs starting from rest if each dog exerts an average force of 185 N backward on the snow.
(b) Calculate the force in the coupling between the dogs and the sled.

Answer 1

a.
`2.86 m/s^2`

b.1058 N

Step-by-step explanation:

We are given that

Mass of each dog,M=18.5 kg

Mass of sled with rider,m=250 kg

a.Average force,F=185 N

`\mu_s=0.14`

`g=9.8 m/s^2`

By Newton's second law

`8F-f=(8M+m)a`

`a=(8F-f)/(8M+m)=(8(185)-(0.14)(9.8)(250))/(8(18.5)+250)`

`a=2.86 m/s^2`

b.By Newton's second law

`T=ma+\mu_s mg`

Substitute the values

`T=250* 2.86+0.14(250)(9.8)=1058 N`

Hence, the force in the coupling between the dogs and the sled=1058 N