Question

Your dog sleeps on the floor. He has a mass of 14 kg. The coefficient of static friction between him and the floor is 0.3, and the coefficient of kinetic friction is 0.25.

a. What is the weight of your dog?
b. What is the normal force acting on your dog?
c. What is the maximum force of static friction?
d. You push horizontally on your dog with a force of 50 N. Does your dog slide?
e. Later, you are sliding your dog across the floor at a speed of 2 m/s. What is the force of kinetic friction acting on your dog?

Answer 1

A.137.2N

B 137.2N

C.41.16 N

D.Yes

E. 34.3N

Step-by-step explanation:

THe weight of any object is calculated by multiplying the mass of the object by the gravity of where they are in, in this case is the earth, the gravity of earth is
`9.8(m)/(s^(2) )`, so the weight of the dog would be:

`w=(14kg)(9.8(m)/(s^(2)))`

`m=137.2 N`

Now the normal force is the same as the weight.

`Nf=w= 137.2N`

The maximum force of static friction is calculated by multiplying the weight by the coefficient of static friction:

`Sf=(w)(coefficient)`

`Sf=(137.2N)(0.3)`

`Sf=41.16`

To know this you just have to know the total static force to know if the dog moves, since the force pulling the dog towards the floor is on the Y axis and you are pushing on the x axis, that force is nulified, but you have the friction froce, which is 41.16N, since the force you are pushing with is 50N the dog moves.

When you are sliding somthing over any surface you just have to multiply the weight of the object by the coefficient kinetic friction.

`Kf=(w)(coefficient)`

`Kf=(137.2N)(.25)`

`Kf=34.3N`