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) weight = mg as usual

Answer 2

I'm going to be doing some volunteer work later this afternoon but hopefully @sillybilly123 or @Nnesha should come on

Answer 3

137.2

Answer 4

oh okay sure no problem

Answer 5

b) normal force is equal to the weight since we are on level ground

c) max static friction is mu_s * N as usual, make sure you are using the coefficient of static friction

d) if 50 > static friction force from c then yes, otherwise no

e) Fnet = F_applied - F_friction = ma
i'm actually not sure where to go from here but that's the setup at least :S

Answer 6

would a be a certain unit?

Answer 7

@Vocaloid

Answer 8

@Vocaloid

Answer 9

units of weight are N

Answer 10

b)14kg

Answer 11

b) normal force is equal to weight not mass

Answer 12

oh shoot read wrong. so just 137.2N for b

Answer 13

oh shoot read wrong. so just 137.2N for b

Answer 14

good

Answer 15

ookay so for c it would be

Answer 16

mu_s * N

Answer 17

okay so it would be (14)*

Answer 18

mu_s = coefficient of static friction

Answer 19

0.3=

Answer 20

good, so mu_s * N = ?

Answer 21

is n the kinetic force

Answer 22

N is the normal force

Answer 23

0.3*137.2=41.16

Answer 24

good

for d) since the applied force > static friction force then yes the dog slides

for e) I'm still not 100% on this but I would guess it's just mu_k * N

Answer 25

N right

Answer 26

for units yes

Answer 27

for e we can just do it whatever you think, because you have been right so far :))))

Answer 28

yeah I'd just go with 0.25 * normal force b/c Idk what else one could do here

Answer 29

0.25 * 137.2=34.3N

Answer 30

good