Question

Help Please!!!!(:
Problem below

Answer 1

@Jemurray3

Answer 2

You know the total mass and acceleration of the system, so what net force must be applied?

Answer 3

I don't know how to apply anything :/ i'm stuck...

Answer 4

What's the total mass of the system?
What's the acceleration of the system?

Answer 5

mass is 1 kg
acceleration is 0.6 m/s^2

Answer 6

It quite clearly says two 100 kg boxes, does it not?

Answer 7

oh yeah,,, 1 kg was the rope.

Answer 8

so one kg for each rope, 100 kg for each box is .... ?

Answer 9

it shows it in the pic? lol

Answer 10

The total mass of the system is 202 kg, agreed?

Answer 11

okay..

Answer 12

where do i go from there? @Jemurray3

Answer 13

So you know the mass and also the acceleration, so what's the total force?

Answer 14

how do i get the total force?

Answer 15

From Newton's second law, F = ma.

Answer 16

202*0.6?
=121.2?

Answer 17

yes

Answer 18

ohhh. how do i get T_A, T_B and T_C?

Answer 19

The tension at point A must be responsible for accelerating everything to the left of point A. That's just the leftmost box in this case.

What is the mass of the box, and what is the acceleration of the box?

Answer 20

mass is 100 and accelereation is 0.6

Answer 21

So the force on it must be what?

Answer 22

60?

Answer 23

@Jemurray3

Answer 24

yes. Now do the same for points B and C. The only thing that changes is the amount of mass that the tension is responsible for pulling.

Answer 25

how do i figure that out. so if for T_B the mass is 100 acceleration is 0.6 wouldn't it just be the same? and do i account for the mass of the rope?

Answer 26

Of course, that's the whole point The mass changes each time. Point B must accelerate the left block AND the left rope, and point C must accelerate the left block AND the left rope AND the right block.

Answer 27

so how do i set the problem up? I'm a bit lost

Answer 28

It's literally exactly what you did before, but substituting the extra mass each time. I'm not doing the rest of the problem for you. You know that all the accelerations are equal to 0.6 m/s^2, to find the tension at a point you just multiply that by the mass to the left of that point. For the first one, T_A, there was 100 kg to the left of point A, so the tension was 100 * 0.6 = 60 N.

Answer 29

I got it!(:

Answer 30

Could you help me with the second problem?

Answer 31

@Jemurray3 the second problem in the attached pic/

Answer 32

What is the gravitational force pulling it down the ramp? Not mg, but the component along the surface of the incline?