Question

If you have a block that is 2.0kg being pulled horizontal to the surface and parallel to the surface. The coefficient of friction is 0.30.

a) What is the acceleration?

b) What is the velocity after traveling for 8 seconds?

c) What is the position after traveling for 8 seconds?

Answer 1

@amistre64

Answer 2

use Newtons 2nd law and compare it with the friction force stuff.

Answer 3

F = ma

F = un

ma = un

a = un/m

Answer 4

In the Force Diagram if I would to make one, would it be equal to the Force of Gravity?

Answer 5

It depends on the force applied. There must be some missing information in your question.

Answer 6

veolcity and position are then just antiderivative constructs of acceleration

Answer 7

Ahhh yea sorry applied force is 10.0N

Answer 8

Try to draw a sketch of the situation with all the forces at stake.

Answer 9

This is the Force Diagram correct?

Answer 10

Correct, but no use to have negative values of forces on your sketch.

Use Fk = µ.Fn = µ.m.g

Answer 11

If not stated otherwise, use g = 10 m/s²

Answer 12

I know I was just generalizing them:

So then Fk would be 5.9N and negative due to the direction it is in?

Answer 13

Then sum of Forces in x direction is 10.0N + (-5.9N) = 4.1

Answer 14

Ok

Answer 15

Then since F = ma

4.1N = (2.0kg)(a)

a = 2.1m/s^2

Answer 16

Correct

Answer 17

that is part a

part b would be using

v = a(dt)

so v = (2.1m/s^2)(8s) = 17 m/s

Answer 18

right?

Answer 19

Yep! if initial velocity is zero.

Answer 20

And position is

x = .5at^2

so x = .5(2.1m/s^2)(8s)^2 = 67m

Answer 21

Yep!

Answer 22

Well done!

Answer 23

Ok thanks! Justn eeded help on first step was all

Answer 24

Remember slipping friction force is always equal to normal force times kinetic friction coefficient.

Answer 25

Yea the part i was questioning was if Normal Force was equal and opposite of Force of Gravity

Answer 26

Can you help me with a few other things?

Answer 27

It was, because the contact is horizontal and no other vertical force is acting on the body.

In different words : vertical acceleration is zero, so net vertical force is zero, so weight and normal force are opposed.

Answer 28

I can help but only a few minutes (must go and sleep).

Answer 29

Can you help me doug?