# M1 helpWatch

#1
can someone explain to me why acceleration is not considered on the highlighted equation, is it cause it is only moving horizontally ?
0
2 years ago
#2
I have done it differently.

If the mass is 8kg, the force going down is 8 * 9.81 = 78.48N
Therefore, the contrasting force, R, is also 78.48N
Which means the friction is 78.48/5 = 15.696N

The pulled object is stationary, therefore the horizontal pulling force must be 15.696N
However, the rope is at 30 degrees from the horizontal. The rope and the ground can form a right angle triangle if a vertical line is drawn.

In this triangle, the adjacent side of the 30 degrees angle has force 15.969N, while the tensione of the rope is unknown and is the hypotenuse.
Furthermore, using CAH,
cos30 = 15.969 / x
x = 15.969 / cos30
x = 18.44N

X is the tension of the rope.
0
2 years ago
#3
(Original post by djmans)
can someone explain to me why acceleration is not considered on the highlighted equation, is it cause it is only moving horizontally ?
It is moving at a steady speed - this means that the acceleration of the system is zero.
0
2 years ago
#4
(Original post by djmans)
can someone explain to me why acceleration is not considered on the highlighted equation, is it cause it is only moving horizontally ?
We are resolving horizontally not using f=ma or an equation
0
2 years ago
#5

The pulled object is stationary, ....
No - the question says it is MOVING at a steady speed.

Please don't post solutions - we only post hints in maths
0
2 years ago
#6
(Original post by Muttley79)
No - the question says it is MOVING at a steady speed.

Please don't post solutions - we only post hints in maths
Oh sorry, I was trying the question so that I could get help, as I am learning this stuff now in class.
So, as the object is moving what do I need to change in my working out?
0
2 years ago
#7
Oh sorry, I was trying the question so that I could get help, as I am learning this stuff now in class.
So, as the object is moving what do I need to change in my working out?
You need to set out properly saying what you are doing.

As system is in equilibrium
Resolving vertically gives: ...

etc

Examiners need to understand what you are doing and why..
0
2 years ago
#8
(Original post by Muttley79)
You need to set out properly saying what you are doing.

As system is in equilibrium
Resolving vertically gives: ...

etc

Examiners need to understand what you are doing and why..
Isn't the system in equilibrium when the object is stationary?
0
2 years ago
#9
Isn't the system in equilibrium when the object is stationary?
Yes - it is vertically.

Also because the object is moving at a steady speed the forces are in equilibrium horizontally as well.

0
#10
Isn't the system in equilibrium when the object is stationary?
check ukmathsteacher or examsolutions for m1 tutorials if you need
0
2 years ago
#11
(Original post by djmans)
check ukmathsteacher or examsolutions for m1 tutorials if you need
Definitely, thank you.
0
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