Question

MEDAL GIVEN TO CORRECT ANSWER.
A television of mass 12 kg sits on a table. The coefficient of static friction between the table and the television is 0.83. What is the minimum applied force that will cause the television to slide?

A. 118 N
B. 98 N
C. 75 N
D. 83 N

Answer 1

You can do this! Try it, tell me your answer. I'll comment.

Answer 2

i'm thinking it's D, but im not completely sure. @douglaswinslowcooper

Answer 3

Noooo...show me your thinking.
What is the definition of coefficient of static friction?

Answer 4

Static is the friction that acts when something is not moving, correct?

Answer 5

Correct. It is the force that you would have to overcome to get the object to start sliding. After than, sliding friction is what you are working against. What is the formula that connects static friction with the weight of the object?

Answer 6

it's w=mg i think.
Which would make the answer A?

Answer 7

Weight = mass times gravitational acceleration is a good start.

The downward force from the television is W = m g.

What is the sideways force you have to apply to start it moving? How does it related to the coefficient of static friction?

Answer 8

static is when it's not moving, so the force you apply is what makes it start moving. Which is considered kinetic friction? @douglaswinslowcooper

Answer 9

kinetic friction is the resistance to motion at a constant velocity due to friction. it is generally less than static friction, which is why when you start to push something, once it gets going it is easier to push than it was to start.

The coefficient of kinetic friction is the frictional force divided by the weight of the object, friction / weight.

What do you think the definition of coefficient of static friction is?

Answer 10

The coefficient os static friction is larger then the coefficient of kinetic friction, right?
The coefficient of static would be the force that resist motion?

Answer 11

That's almost correct.

Static friction is the resisting force at the start, the heavier the item, the bigger it would be

static friction force Fsf = (Csf)( W)

weight is a force (newtons), so is friction, so Csf = Fsf/W has
no units, which is why it is called a "coefficient."

We are up to Fsf (newtons) = (0.83) (weight = m g, newtons)

calculate m g = ?

then calculate Fsf = ?

What do you get?

Answer 12

mg = 117.6
how do you calculate Fsf?

Answer 13

Now that you have the weight, the static friction is 83% of it,

Fsf = Csf W

friction = (0.83) (weight)

Calculate and celebrate.

Answer is?

Answer 14

Are you still there? Have you survived?

Answer 15

haha, barley.
but it's 98 N?

Answer 16

Soooo good!

That's how the site wants me to interact with the students. I hope you felt the pain was worth the gain. Regards.